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285 Cards in this Set
- Front
- Back
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why are antimicrobial drugs effective in treatment of infections?
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Because of their selective toxicity-the ability to injure or kill an invading organism without hamring the host
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What does it mean that selective toxicity is relative rather than absolute in antimicrobial drugs?
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the concentration of the drug must be controlled to attack the organism while still being tolerated by the host
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What is empiric therapy and when would it be required?
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it is the immediate administration of a drug before the bacteria has been identified. useful in critically ill patients.
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How does gram staining help determine treatment?
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it helps to identify the characteristics of the organism. very helpful when used to identify organisms that are found in otherwise sterile parts of the body
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Why is it usually necessary to culture the infective organism?
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helps arrive at a conclusive diagnosis and determine the susceptibility of the bacteria to antimicrobial agents
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What should you consider when selectiving a drug in the absence of susceptibility data?
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site of infection, patient's history, hospital or comm. acquired, travel record, age, and immunocompromised?
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when the identity of the organism is unknown and it's a serious infection what type of drug should you chose?
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a broad specturm antibiotic-this should also be choosen if the site of infection makes a polymicrobial infection likely
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What pathogens have predictable susceptibilty patterns?
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Strep pyogenes and N. meningititis
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What types of pathogens show unpredictible susceptibility patterns?
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most gram negative bacilli, entercocci, and staph species
These require susceptibility testing |
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What does bacteriostatic mean?
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the drug stops the growth and replication of the bacteria at serum levels acheivable in the Pt
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How does a bacteriostatic drug help to get rid of an infection?
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stops grow which allows the body's immune system to attack and stop the spread of infection. The body actually eliminate the pathogen, not the drug.
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What do bacteriocidal drugs do?
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Kill the pathogen at serum levels acheivable in the patient
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What drug would you chose for a seriously ill patient? static or cidal?
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Cidal because they are more aggresive. Many drugs can be both static and cidal depending on the pathogen present
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What is MIC?
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Minimum inhibitory concentration. the lowest concentration of antibiotic that inhibits bacterial growth
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Where should levels of antibiotic be in relation to MIC?
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the antibiotic concentration in body fluids should be GREATER than the MIC to provide effective antimicrobial therapy
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What is MBC?
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Minimum bacteriocidal concentration. the lowest concentration of drug that results in 99.9% decline in colony count
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Where are natural barriers to drugs located in the body?
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prostate, vitreous body of the eye, CNS, and capillaries of some tissues.
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What is the BBB?
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Blood brain barrier. it is the barrier formed by a single layer of endothelial cells fused by tight junctions that stop drug entry into the CNS
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What types of molecules can pass through the BBB?
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small and lipophilc(fat loving)
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What are lipophilc drugs that can penetrate the CNS?
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quinolones and materonidazole
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when can lipophobic drugs cross the BBB and what are those drugs?
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penicillin and B-lactams are lipophobic and therefore cannot penetrate the CNS effectively unless the barrier is inflamed. Meningitis increases permeability of these drugs into the CNS
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How does molecular weight of a drug effective it's ability to cross the BBB?
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low molecular weights cross easier than higher weights(such as vancomycin). Vancomyocin still doesn't penetrate well even during meningitis
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How does protein biding of the drug effect it's entrance into the CNS?
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high degree of protein binding decreases it's ability to cross. Free (unbound) drug in serum is important when considering CSF penetration
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What are patient factors that must be considered before writing a prescription?
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Renal dysfunction, hepatic dysfunction, poor perfusion(diabetics), age, pregnancy, lactation, and immune state(such as in HIV).
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what measurement is often used to determine kidney function?
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serum creatinine levels.
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Who are vulnerable to drugs that are renally excreted and why?
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elderly because functioning nephrons decrease with age. the drugs can accumulate in the elderly because they are not being properly excreted
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How does perfusion effect antibiotic use?
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poor perfusion in diabetics to lower limbs reduces the amount of antibiotic that reaches the area making an infection in that area hard to treat
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how does age effect treatment options with antibiotics?
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newborns have poorly developed renal and hepatic elimination processes. Tetracyclines effect bone growth
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What drug has an ototoxic effect on the fetus during pregnancy?
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Aminoglycosides
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Can drugs cross the placenta or into the breast milk?
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yes-all drugs have been found to cross the placenta. Drugs can also cross into the breast milk
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when is oral administration ok?
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for mild infections that are outpatient based
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When can you switch to oral drugs if you're on an IV therapy?
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after initial IV therapy the Pt is switched to oral therapy A.S.A.P
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What is concentration-dependant killing?
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drugs that show an increase in rate of killing as the concentration of the drug increases
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name of some examples of concentration-dependant killing drugs
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Aminoglycosides and Fluoroquinolones-often given in one day bolus to acheive high peak levels which favors rapid killing
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What does concentration-independant or time-dependent killing mean?
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it means the effects of the drug are based on the percentage of time that blood concentrations of the drug remain above MIC.
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Name some time-dependent drugs
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B-lactams, Glycopeptides, Macrolides, Penicillins, cephalosporins, and Clindamycin
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what percentage above MIC should a drug be to be clinically effective?
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60-70% above MIC
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what is the PAE?
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post-antibiotic effect-how long the pathogen still isn't growing even after the drugs levels fall below the MIC
(length of time is takes for the pathogen to acheive log phase growth) |
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Would a drug that has a long PAE need to be taken less often a day of more often a day? examples of drugs with long PAE?
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longer PAE(several hours) need to be taken less often. Examples; Aminoglycosides, and Fluoroquinolones
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What does narrow-specturm mean and give an example of a drug?
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Isoniazid (active only against mycobacteria) Drug that is active against only 1 or a few pathogens
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What does extended-spectrum mean? example?
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effective against gram-positive and a significant amount of gram negative. Example: Ampicillin
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What is Broad-spectrum? Examples?
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Effect a wide variety of pathogens. Tetracycline and Chloramphenicol
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Why wouldn't you use a borad spectrum antibiotic?
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they can effect the normal flora in your body or can cause a superinfection(such as Candida albicans.
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Why treat with the most specifc drug for a pathogen?
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reduces the chance of superinfections, decrease antibiotic resistance, minimizes toxicity
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What are the advantages of drug combos?
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Synergism-two drugs increase each other effectiveness
Examples: B-lactams and aminoglycosides, combos are also used for infections of unknown origins |
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What is drug resistance?
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bacteria are reistant when their growth is not stopped by the max level of drug that the host can tolerate
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How can pathogens become resistant?
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spontaneous mutations of acquired resistance and selection.
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What DNA changes can help pathogens become resistant?
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spontaneous mutations (insertion, deletion, or substitution of nucleotides) and DNA transfer of resistance
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What are the mechanisms of resistance that bacteria can undergo?
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Modification of target sites, decreased accumunlation within the pathogen(decreaesd uptake-through less proins ofr increaed efflux), Enzymatic Inactivation(B-lactamases of penicillinases)
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What sitituations require prophylactic antibiotics?
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1)prevention of streptococcal infx in Pt with Rheumatic Heart Disease
2) Pt having tooth surgery that has atrificial heart valve 3) prevention of TB of meningitis 4)Tx prior to surgery 5) Tx of prego HIV women with zidovudline |
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What are complications of antibiotic Tx?
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Hypersensitivity, Direct Toxicity, Superinfections
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what types of drugs require actively dividing organisms in order to be effective?
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Inhibitors of cell wall synthesis such as the B-lactam antibiotics. and Vancomycin.
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what are the different types of B-lactam antibiotics?
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Penicillins
Cephalosporins(with 4 generations) Carbapenems Monobactams |
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Where do penicillins interfere?
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with the last step of bacterial cell wall synthesis which exposes the membrane that water can penetrate. This allows cell lysis to occur.
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Are penicillins static or cidal?
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Cidal because they allow for cell lysis.
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How are gram-negative bacteria susceptible to antibiotics?
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They have porins which let the drug enter into the cell (transmembrane entry)
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Why is P. aeruginosa so resistant?
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it lacks porins
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what penicillin is most often used for gram-positive, and gram-negative cocci, gram pos bacilli and spirochetes?
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Penicillin G (benzylpenicillin
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Which penicillin is susceptible to inactivation by B-lactamases(enzymes)?
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Penicillin G
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What are the classification of Penicillins?
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1)Natural
2)Antistaphylococcal 3)Extended-spectrum 4) Antipseudomonal 5)Penicillins and Aminoglycosides |
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Types of antistaphylococcal penicillins
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Methicillin
Oxacillin Cloxacillin Dicloxacillin They are all penicillinase-resistant |
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What is methicillin used for and what treats MRSA?
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it's used to identify types of MRSA and not used for treatment because of it's toxicity. Vancomyocin is used to treat MRSA
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Types of extended-spectrum penicillins
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Ampicillin
Amoxicillin More effective against gram negatives than Pen. G |
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when are extended spectrum penicillins used?
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to treat Resp. tract infections and amoxicillin is used by dentists for Pt with artificial heart valves
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What helps protect extended spectrum penicillins from B-lactamases? Examples?
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Mixing them with clavulanic acid or sulbactam.
Augmentin(amox and clav) Unasyn(ampicillin and sulb) |
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Examples of antipseudomoncal penicillins
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Indanyl carbenicillin
Ticarcillin Piperacillin -All active against P. aeruginosa |
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what are B-lactam antibiotics synergistic with?
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Aminoglycosides
-the B-lactams allow the aminoglycosides to enter the pathogen easier |
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How do B-lactamases work to allow for pathogen resistance?
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hydrolyze the B-lactam ring of the drug which causes it to lose it's cidal activity
-main cause of resistance to penicillins |
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What penicillins must be administered IV or IM?
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Ticarcillin
Carbenicillin Piperacillin Unasyn(ampicillin and sulbactam) "Ticarcillin and clavulanic acid" Zosyn(piperacillin with tazobactam) |
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Which penicillins are ONLY oral?
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Penicillin V
Amoxicillin Augementin(amox and clav) Indanyl Carbenicillin(for UTIs) |
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whic penicillins are used in depot forms?
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Procaine penicillin G and benzathine penicillin G
-IM injection, slowly absorb and persistant at low levels over long periods of time |
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Typical absoprtion of oral penicillins
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incompletely absorbed orally and don't usually effective gut flora
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Which penicillin is almost completely absorbed orally and what is it contraindicated for?
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Amoxicllin
Don't use for Shigella or Salmonella enteritis |
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what is the distribution of B-lactames?
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GOOD throughout the body
all penicllins cross the placenta but are not teratogenic Don't penetrate bone of CSF unless inflammed |
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what are the safest drugs?
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penicillins
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what are the adverse reactions to penicllins?
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1)hypersensitivity 5% of Pt(maculopapular rash, angioedema, anaphylaxis)
2)diarrhea 3)nephritis 4)neurotoxicity 5)hematologic toxicities 6)cation toxicity |
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what's the benefit of using a cephalosporin instead of a penicillin?
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they have higher resistance to B-lactamases but are still ineffective against MRSA
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what are second generation cephalosporins used for?
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greater activity against gram negative organisms: H. influenzae, Enterobacter aerogenes, and some Neisseria
-weaker gram positive activity |
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what is the role of 3rd generation cephalosporins? Examples?
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more activty against gram negative bacilli
Examples: Ceftriaxone-Tx against meningitis |
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4th generation cephalosporin roles? Examples?
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wide antibacterial spectrum including P. aeruginosa
Example: Cefepime |
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adverse effects of cephalosporins?
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1) Allergic reaction(Pt with anaphylacit rxn to penicllin can't use cephalo. but others can with caution)
2) Disulfiram-like effect(cefamandole/cefoperazone used with alcohol-blocks the alcohol oxidation and causes acetaldehyde to accumulate) 3) Bleeding |
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what is the spectrum of carbapenems? Examples?>
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broadest spectrum B-lactams available.
Imipenem/cilastatin and Meropenem. Kills P. aeruginosa!!!! |
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Why are monobactams unique among the B-lactams?
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they're B-lactam ring is not fused to another ring
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Example of a Monobactam? What does it kill?
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Aztreonem-only one available
Kills Enterobacteriaceae and P. aeruginosa! |
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When is Aztreonem NOT used? what type of B-lactam is it?
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it's a monobactam and it's not used empirically because it has a narrow spectrum
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What are examples of B-lactamase inhibitor drugs? How do they work?
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Clavulanic acid
Sulbactam Tazobactam -have a B-lactam ring but little antimicrobial activity so they bind to the B-lactamases and protect the antibiotics |
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What is vancomycin? why is is important?
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Tricyclic glycopeptide
Effective against MRSA and enterococci |
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what is vancomycin effective against?
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gram positive organisms, MRSA, MRSE, and enterococcal infections
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what organisms are vancomycin resistant?
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Enterococcuse FAECIUM
Enterococcuse FAECALIS |
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When is vancomycin given orally?
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antibiotic-associated colitis due to C. difficile
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what can treat vancomycin resistant organisms E. faecium and E. faecalis?
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Quinopristin/dalfopristin
Linezolid |
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why is vancomyocin usually not used orally?
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it isn't absorbed
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adverse effects of vancomycin use?
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fever, chills, phelbitis
Flushing "red man syndrome" Shock-due to histamine release Otoxicity/Nephrotoxicity(when given with another drug) |
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what do protein syntheiss inhibitors target?
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ribosomes
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why can targeting bacteria ribosomes be problematic?
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our mitochondiral ribosomes are very familiar so high levels of drugs (chloramphenical/tetracyclines) may cause toxic effects with mitochondrial ribosomes
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Types of tetracyclines?
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Doxycycline(Doryx)
Minocycline(Minocin) Tetracycline(Sumycin) |
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Types of macrolides/ketolides
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Azithromycin(Zithromax)
Clarithromycin(Biaxin) Erythromycin(Ery-Tab) Telithromycin(Keteic) |
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Groups of protein syntheiss inhibitors
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Tetracyclines
Aminoglycosides Macrolides/Ketolides Chloramphenical Clindamycin Quinupristin/Dalfopristin Linezolid |
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what is the specturm of tetracylcines and what are they effective against?
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Broad spectrum, bacteriostatic, effective against gram-positive, and gram negative bacteria and some organisms that are not bacteria
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what's the problem with tetracycline resistance?
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It's widespread
Organism resistant to one is resistant to all Many penicillinase-producing staph are resistant to tetracyclines |
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What effects absorption of tetracyclines?
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Diary foods decreases absorption by forming nonabsorbable chelates of the drug with Ca ions.
Thesea can also be formed from Mg, Al antacids, and Fe. |
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What is unique about the distribution of tetracyclines in the body that makes it contraindicated in chlidren and pregnant women?
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It binds to tissues undergoing calcification (teeth and bones)
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What tetracyclic drug is unique in it's excretion? What is the normal route for excretion of tetracyclines?
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Doxycycline is excreted via the bile duct into the feces. Other tetracyclines are eliminated in the urine
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What are the adverse effects of tetracyclines?
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Gastric Discomfort
Effects of Calcified Tissues Fatal Hepatotoxicity Phototoxicity Vestibular Problems(w/ Minocycline) Pseudotumor Cerebri(blurred vision/headache-reversible) Superinfections(Candida) |
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When are tetracyclines contraindicated?
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Renally impaired Pt exceptiong treatment with doxycyline
Young child Pregnant/Breat feeding women |
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What drug is choosen first for very serious infections due to AEROBIC gram-negative bacilli?
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Aminoglycosides
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Why are aminoglycosides dangerous and what drugs replace them?
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because of serious toxicities
3rd generation Cephalosporins Fluoroquinolones Imipenem/Cilastatin |
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How do aminoglycosides work?
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Bacteriocidal
enter through porins and interfers with ribosomes assembly |
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What type of drugs increases the effectiveness of aminoglycosides? what is this process called?
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B-lactam antibiotics or Vancomycin
Synergism |
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When are aminoglycosides used?
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Empirically
Works against P. aeruginosa |
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name four common aminoglycosides
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Amikacin
Gentamicin Tobramycin Streptomycin |
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How must all aminoglycosides be administered? What's the exceptiong?
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Parenterally(not orally)
Neomycin-only used topically because of nephrotoxic effects |
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Five disease treated by tetracyclines and each disease drug of choice:
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1)Chlamydial Infections-Doxycycline
2)Rocky Mt Spotted Fever-tetrecyclines(not specified) 3)Mycoplasma pneumonia-Erythromycin 4)Lyme-Doxycycline 5)Cholera-Doxycycline |
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How do you treat enterococci infections?
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two synergistic drugs: Gentamicin or streptomycin
AND Vancomycin or B-lactam(such as Penicillin G) |
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How do you treat P. aeruginosa? In who does it commonly affect?
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In burn victims or immunocompormised Pt.
Tx: Tobramycin alone or with piperacillin or ticarcillin |
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Where do aminoglycosides commonly accumulate? What effects does this cause?
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Renal cortex, endolymph and perilymph of the inner ear
Ototoxicity and Nephrotoxicity |
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what shoudl you monitor in a Pt that's taking an aminoglycoside? Why?
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Plasma levels, to avoid dose related toxicity. Monitor the elderly closely
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What are four adverse effects of aminoglycosides?
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Ototoxicity(destroys hair cells in the Organ of Corti)
Nephrotoxicity(acute tubular necrosis) Neuromuscular Paralysis(decreases Ach release) Allergic Reaction |
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who is more at risk for ototoxicity from aminoglycosides?
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Pt on loop diuretics, ethecrynic acid, or cisplatin
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What can you give to reverse neuromuscular blockade caused by an aminoglycoside? who is at higher risk?
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Neostigmine
Pt with Myasthenia Gravis |
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what was the first macrolide drug? when is it used?
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Erythromycin
alternative to penicillin |
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Besides erythromycin, name three macrolide drugs.
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Clarithromycin
Azithromycin Teithromycin |
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How do macrolides work against bacteria?
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Usually static but can be cidal at higher doses. Inhibits the translocation steps of proetin synthesis
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erythromycin has a similar spectrum to what other drug?
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Penicillin G
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what is the treatment of choice for urethritis caused by Chlamydia trachomatis? what else is this drug good for?
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Azithromycin(a macrolide drug)
Mycobacterium avium-intracellulare complex in AIDS Pt |
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most strains of staphylococci in hospitals are resistant to what macrolide?
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Erythromycin
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which macrolide can still be effective against pathogens that are resistant against macorlides?
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Telithromycin
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what is unique about the distribution of erythromycin in the body>
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penetrates the prostatic fluid
accumulates in macrophages |
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which macrolide has the longest half-life and largest volume of distribution?
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Azithromycin
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What are adverse effects of macrolides?
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1)Epigastric distress-common and can lead to poor Pt compliance
2)Cholestatic jaundice-from estolate forms of erythromycin 3)Ototoxicity 4)Interactions |
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when are macrolides contraindicated? why?
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Pt with hepatic dysfunction because they all accumulate in the liver
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when are chloramphenical drugs used? why?
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only in life-threatening infections with no alternatives. because of their toxic effects
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what is the action of chloramphenical?
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inhibits protein synthesis
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spectrum for chloramphenical?
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broad spectrum
NOT P. aeruginosa good for anerobes static or cidal depending on the organism |
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Adverse effects of Chloramphenical:
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1)Anemias
2)Gray Baby Syndrome 3) Interactions |
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what type of fatal adverse effect can occur from chloramphenical usage?
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Aplastic Anemia
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What drug is commonly used to treat anerobic bacterial infections such as Bacteroides fragilis(abdominal infx related to trauma)?
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Clindamycin
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what's the most serious side effect of clindamycin?
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Pseudomebranous colitis-caused by C. diff overgrowth
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what drugs can control pseudomembranous colitis caused by C. diff?
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Metronidazole or if that doesn't work THEN Vancomycin
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What is Quinupristin/Dalfopristin made of? another name?
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Synercid.
made of: two streptogramins-30:70 ratio |
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when is synercid(quin/dal) used?
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when treating vancomycin-resistant enterococcus faecium (VRE)
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what is funny about synercid(quin/dal) when treating VRE infections?
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It works against E. faecIUM but not E. FaecALIS
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what mechanism of action helps synercid(quin/dal) to be effective against E. faecium?
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it is given through IV and it can penetrate macrophages and PMN. this if important becaseu E faecium is intracellular
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what are adverse effects of synercid(quin/dal)?
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1)Venous Infections
2)Arthralgias/Myalgias 3)Hyperbilirubinemia 4)Interactions |
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what is linezolid/Zyvox effective against?
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resistant gram positive organisms MRSA/VRSA/VRE (both types of VRE) and penicillin-resistant streptococci
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what adverse effect of linezolid was found in 2% of Pt?
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Thrombocytopenia-in Pt that were on the drug for longer than 2 weeks
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What mechanism of action does Linezolid use?
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inhibits protein synthesis
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What are the major categories of drugs that work by protein synthesis inhibition?
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1)Tetracyclines
2)Aminoglycosides 3)Macrolides/Ketolides 4)Chloramphenical 5)Clindamycin 6)Quinupristin/Dalfopristin 7)Linezolid |
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what are also known as urinary tract antiseptics?
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quinolones
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How are fluoroquinolones classified?
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By generations 1st, 2nd, 3rd, 4th
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How do the new fluoroquinolones(FQs) compare to the older compounds?
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more active against gram-positive and retain activity against gram-negative.
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What are people doing that is creating resistance to FQs?
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OVERUSE!
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Mechanism of action of FQs?
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invade cell through porins then interfere with DNA gyrase which inhibits cell replication
BACTERIOCIDAL! |
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Name some new agents of FQSs. what are they better for than the older agents?
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Levofloxacin
Gatifloxacin good activity against Gram POSITIVE (like Strep pneumoniae) |
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What is a 1st generation FQ?
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Nalidixic acid
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2nd generation FQs?
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Ciprofloxacin
Levofloxacin Norfloxacin -due to their activty against systemic aerobic gram-negative infections |
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3rd generation FQs?
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Sparfloxacin
Gatifloxacin -increased activty against gram positive and atypical pathogens |
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4th generation FQs?
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Only Trovafloxacin
-active against anaerobic and gram positive organisms |
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which FQ is used for treating enterobacteriaceae and other gram negative bacilli? Give axamples of pathogens it kills.
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Ciprofloxacin
-traveler's diarrhea caused by E. coli -Anthrax -P. aeruginosa |
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What is levofloxacin used for?
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Prostatitis due to E. coli
STD's but NOT syphillis skin and lower resp tract infections |
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Which FQs (2) would you chose to treat a respiratory infection? what generation are they
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Levofloxacin(2nd gen)
Gatifloxacin(3rd gen) -active against S. pneumoniae |
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adverse reactions from FQs:
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1)GI -nausea, vomiting, diarrhea
2)CNS problems-dizzy, headache (Ciprofloxacin may cause seizures) 3)Phototoxicity 4)Liver Toxicity(trovafloxacin-used rarely) 5)Connective Tissue problems-ruptured tendons |
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what are the contrindications for FQ use?
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People with long Qts because these drugs will prolong them even more
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What drugs inhibit folic acid synthesis?
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Sulfa drugs (sulfonamides)
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what does trimethoprim do?
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it's a folic acid antagonist-prevents it from being active
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what's the normal administration of sulfa drugs? exceptions?
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Normally oral except in burn victims when creams of silver sulfadiazine of mafenide acetate are used to decrease sepsis(by preventing colonization of bacteria)
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adverse effects of sulfa drugs?
|
1)Crystalluria
2)Hypersensitivity 3)Hemopoietic disturbance 4)Kernicterus 5)drug potentiation |
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what is kernicterus and how does it occur?
|
sulfa drugs displace bilirubin from binding to serum albumin. This occurs in newborns and the bilirubin is free to pass through the CNS becaues the BBB isn't fully developed.
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what is co-trimoxazole?
|
combo of Trimethoprim and sulfa-methoxazole
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when is trimethoprim used alone?
|
UTIs
bacterial prostatitis Vaginitis |
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adverse effects of trimethoprim?
|
folic acid deficiency
megaloblastic anemia, leukopenia. Can be reversed if given folinic acid |
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Name brands of co-trimoxazole?
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Bactrim
Septra |
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why use co-trimoxazole?
|
because it's better than trimethoprim or sulfamethoxazole used alone
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how does co-trimoxazole's spectrum compare to sulfa drugs?
|
it's a broad spectrum than the sulfa drugs
Treats UTIs, RTI |
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Adverse effects of co-trimoxazole?
|
1)Dermatologic
2)GI 3)Hematologic: megaloblastic anemia-reversed if given folinic acid 4)HIV patients 5)drug interactions |
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the most common types of UTIs? who are these mostly seen in?
|
uncomplicated acute cystitis
pyelonephritis Women and elderly |
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Most common pathogen causing UTIs? 2nd?
|
E. coli
2nd-Staphylococcus saprophyticus |
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name some urinary tract antiseptics
|
Methenamine
Nitrofurantoin Naladixic acid(quinolone) |
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what is unique about urinary tract antiseptics?
|
they don't acheive high concentration in the blood but are high enough in the urine to kill bacteria located there
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what are the brand names of Nitrofurantoin
|
MacroBid
Macrodantin |
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why is nitrofurantoin not as commonly used in treating UTIs?
|
narrow spectrum and toxic
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if you're not sure if the UTI is caused by E. coli what urinary antiseptic would you NOT want to use?
|
Nitrofurantoin because it's useful against E. coli but not against other gram-negative bacteria(resistance)
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what are considered "acid fast"? what does that mean?
|
Mycobacteria
It means their walls are not penetrated by the gram stain |
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what are some common diseaes caused by Mycobacteria?
|
TB and leprosy
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what's unique about mycobacteria's infection process?
|
They are intracellular and result in slow growing granulomatous infections.
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what type of microbial agents are recommended for anitTB therapy?
|
1st line antimicrobial agents
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what about 2nd line antimicrobial agents?
|
less effective
more toxic not been studied enough |
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what's the treat time for TB and why?
|
6 months to 2 years because it is slow growing
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what type of therapy is used to treat TB? why?
|
mutlidrug therapy. to delay or prevent the emergence of resistant strains
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name some drugs used to treart TB
|
Ethambutol
Isoniazid Pyrazinamide Rifampin Streptomycin |
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drugs used to treat leprosy?
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Clofazmine
Depsone Rifampin |
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what drug can be used against TB and leprosy?
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Rifampin
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what are the requirements when picking antiTB therapy?
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minimum of 2 drugs
usually both being bactericidal therapy continues well past when symptoms stop |
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what's the short course of TB treatments?
|
Isoniazid, Rifampin, and pyrazinamide for 2 months then just isoniazid and rifampin for the next 4 months
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what other drugs can be added to the short course of TB therapy?
|
Ethambutol or streptomycin
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why is Pt compliance low in TB therapy? how can you increase it?
|
because of mutliple drugs being used and the length.
"Directly observed therapy" can help-this is when Pt is obsrved while taking the meds |
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what anitTB drugs is most potent?
|
Isoniazid (INH)
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what are the adverse effects of isoniazid INH?
|
1)peripheral neuritis(paresthesa)-most common caused by pyridoxine deficiency, can be corrected by B6 supplements
2)Hepatitis |
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what is the spectrum of Rifampin?
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bacteriocidal for intra/extracellular mycobacteria. good for gram + and -.
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what is the best leprosy drugs we know of?
|
Rifampin-but given in combos to reduce the chance of resistant organisms emerging
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What is Pyrazinamide?
|
it's an antiTB drug given in combo with Isoniazid and rifapim
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what antiTB drug is more bacteriostatic and also works against M. kansasii?
|
Ethambutol
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what's the most imporant adverse effect seen with Ethambutol therapy?
|
Optic neuritis-bad visual acuity, colorblindness
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what other drug types can be used against TB? Examples
|
Fluoroquinolones-Ciprofloxacin and Levofloxacin
Macrolides-Azithromycin and Clarithromycin(used for M. avium intracellulare) |
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what macrolide is choosen to treat TB in an HIV infected Pt?
|
Azithromycin because it doesn't interact with the antiretrovirl drugs
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Another name for Leprosy?
|
Hansen disease
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what drug regimen is recommended for treating leprosy?
|
Triple therapy of:
Dapsone, Clofazmin, and Rifampin |
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What's Dapsone?
|
related to sulfonamides and bacteriostatic for M. leprae
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what is Dapsone used to treat?
|
M. leprae
Pneumocystis jiroveci-(causes pnemonia in HIV Pt) |
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what is Clofazimine used to treat?
|
M. leprae
M. avium-intracellulare |
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what does HTN result from?
|
increase peripheral vascular smooth muscle tone, which increase ateriolar resistance, and reduced capacitance of the venous system.
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what is the most common form of HTN?
|
Essential HTN(90%of cases)-unknown causes
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who is at highest risk for HTN?
|
black, males, middle-aged
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what drugs must you be careful of taking while on antiHTN meds? why?
|
NSAIDS because they interfere with antiHTN mechanisms
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what are they main categories of antiHTN drug therapies?
|
Diuretics
B-Blockers ACE Inhibitors Angiotensin II-Receptor Antagonist Ca Channel Blockers Alpha-Blockers Other |
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what controls cardiac output and preipheral resistance?
|
baroreflexes(sympathetic nervous system)
renin-angiotensin-aldosterone system |
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how do most antiHTN drugs work to lower BP?
|
reducing cardiac output and/or decreasing total peripheral reistance
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expalin the renin-angiotensin-aldosterone system.
|
baroreceptors in the kidney respondto decreased pressure by releasing renin-this converts agiontensinogen into angiotensin I which is converted to Angiotensin II by ACE
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what is the bodies most potent cirulating vasoconstrictor? how does it work?
|
Angiotensin II. stimulates aldosterone secretion which increases Na reabsorption and increases blood volume
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|
what is the drug therapy for mild hypertension?
|
one drug-usually thiazide diuretic is initiated. If not controlled with this a second drug is added (usually a beta-blocker)
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what is the treatment of choice for black Pt's with HTN? what drugs don't usually work?
|
diurectics or Ca channel blockers work well. B-blockers and ACE inhibitors don't work as well.
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What drugs are chosen for elderly with HTN?
|
Diuretics, Ca channel blockers, and ACE inhibitors
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|
what is the most common reason for failure of antiHTN therapy?
|
lack of patient compliance
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what are some reason Pt do not comply with antiHTN therapy?
|
decreased libido
Impotence -pick a drug that minimizes these effects and is a low number of doses a day |
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|
what is the 1st line of therapy for HTN?
|
Diuretics-these are better than B-blockers in older adults
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|
Name some thiazide diuretics
|
Hydrochlorothiazide
Spironolactone |
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|
mechanism of action of thiazide diuretics?
|
increases Na and H2O excretion which decrease peripheral resistance but with long-term Tx plasma volume is normal
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|
what is Spironolactone?
|
A K sparing diuretic
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When should thiazide diuretics not be used?
|
In elderly because of postural hypotension. In Pts with poor renal function (creatinine clearance below 50mL/min)
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|
what other type of diuretic can you use with Pt that have poor renal function?
|
Loop diuretic
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|
adverse effects of thiazide diuretics
|
hypokalemia
hyperuricemia hypomagnesemia hyperglycemia |
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|
what electrolyte do you need monitor in Pts on thiazide diuretics?
|
Potassium levels. Also in Pt with arrythmias, or on diuretics and digitalis glycosides
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what is the main difference between loop and thiazide diuretics?
|
loop increase Ca in urine but thiazide decrease Ca in urine
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when would a beta-blocker be the 1st drug for treating HTN?
|
in patients with heart failure.
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|
how do beta-blockers work?
|
decrease cardiac output. inhibit the release of renin.
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|
what's the main beta-blocker drug?
|
Propranolol-acts on B1 and B2 receptors
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|
which beta blockers are selective and what are they selective for?
|
Metoprolol-B1
Atenolol-B1 |
|
|
what makes b-blockers contraindicated?
|
COPD, asthma, CHF, peripheral vascular disease. matoprolol and Atenolol may be used with caution but not propranolol
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|
who are b-blockers more effective in?
|
white Pts and in younger Pts
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|
Adverse effects of beta-blockers
|
bradycardia
fatigue lethargy insomnia decreased libido Impotence |
|
|
what effect do beta-blockers have on cholesterol?
|
decrease HDLs and increase triacyglycerides
|
|
|
what coexisintg conditions in Pt would benefit from prescribing beta-blockers?
|
SVT
previous MI Angina CHF migraines |
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|
when are ACE inhibitors used? name some of them.
|
when beta-blockers are contraindicated or ineffective.
Enalapril LIsinopril |
|
|
When are thiazide diuretics contraindicated?
|
gout
sulfa allergy low creatinine clearance (less than 50mL/min) |
|
|
how do ACE inhibitors work?
|
reduces peripheral vascular resistance without increasing cardica output, rate, or contractility.
|
|
|
what are the effects of bradykinin?
|
vasodilation
|
|
|
what other disease processes do ACE inhibitors help with?
|
slow progression of diabetic nephropathy
decreased albuminuria helpful in chronic heart failure standard of care of Pt with a history of MI |
|
|
adverse effects of ACE inhibitors
|
dry cough, rash, fever, altered taste, hypotension
Hyperkalemia-Potassium levels must also be monitored and no supplements can be taken |
|
|
why does ACE cause dry cough?
|
because of increased levels of bradykinin in the pulmonary tree.
|
|
|
how are ACE inhibitors first administered? why?
|
in the Dr office because of angioedema and first dose syncope
|
|
|
what type of people should NOT use ACE inhibitors?
|
Pt with renal artery stenosis-because of renal failure.
Pregnant women-because it's fetotoxic |
|
|
what are ARBs, when are they used, and name one.
|
angiotensin II-receptor blockers
alternatives to ACE Losartan-protoype |
|
|
what do ARBs do?
|
vasodilation
block aldosterone secretion |
|
|
adverse effects of ARBs?
|
similiar to ACE except less dry cough, angioedema. Also fetotoxic
|
|
|
what are the three classes of Ca channel blockers?
|
1)Diphenylalkylamines
2)Benzothiazepines 3)Dihydropyridines |
|
|
Name a diphenylalkylamine and explain it's uses.
|
Verapamil-least selective Ca channel blocker
effects cardiac and smooth muscle cells Tx:SVT, angina, and migraines |
|
|
Name a benzothiazepine. what's different about it from the other Ca channel blockers?
|
Diltiazem-less pronounced negative inotropic effects
|
|
|
Explain Dihydropyridines. why are they special Ca channel blockers?
|
have mutliple generations
1st gen-Nifedipine 2nd gen-Amiodipine -greater affinity for vascular Ca channels than in the heart(so they're really good for HTN) |
|
|
explain how Ca effects muscles
|
Ca enters though voltage selective Ca channels, triggers the release of Ca from sarcoplasmic reticulum
|
|
|
how do Ca channel blockers work?
|
they block inward movement of Ca by binding to the L-type Ca channels in the heart and in smooth muscle
|
|
|
what other drugs are usually prescribed with Ca channel blockers? why?
|
none because they have an intrinsice natriuretic effect(therefore diuretics wouldn't be helpful)
|
|
|
adverse effects of Ca channel blockers
|
Constipation
dizziness headache |
|
|
what Ca channel blocker should NOT be given to Pt with CHF?
|
Verapamil because it has negative inotropic effects
|
|
|
name some alpa-adrenoceptor blockers
|
Prazosin
Doxazosin Terazosin |
|
|
how do a-blockers work?
|
relax arterial and venous smooth muscle
|
|
|
what do you need to watch for in Pt taking a-blockers?
|
Postural Hypotension, reflex tachycardia, and first-dose syncope
|
|
|
what stops the reflex tachycardia seen in a-blockers?
|
b-blockers
|
|
|
name the centrally acting adrenergic drugs
|
Clonidine
a-Methyldopa |
|
|
what is clonidine?
|
a2-agonist which decreases central adrenergic outflow
-usually given with a diuretic because it causes Na and H2O retention |
|
|
what is a-Methyldopa? what does it do? when is it especially helpful?
|
a2-agonist decreases adrenergic outflow from the CNS
-Cardiac output is not decreased -blood to kidney's is not decreased so it's helpful in Pt with renal failure |
|
|
name some vasodilators
|
Hydralazine
MInoxidil -not used as primary drugs to treat HTN |
|
|
what do hydralazine and minoxidil do?
|
decrease vascular resistance however: increase heart rate, O2 consumption, and contractility-which can cause angina and MI
|
|
|
what should you prescribe along with a vasodilator to decrease it's side effects?
|
diuretic or beta-blocker
|
|
|
When is hydralazine useful? in what type of Pt? side-effects?
|
pregnancy induced HTN
-lupus like symptoms(reversible) |
|
|
what is unique about the dilation seen with Minoxidal use?
|
dilates arteriols but not venules
|
|
|
when is Minoxidal used? What is a side-effect that can actually be useful?
|
in severe HTN when other drugs aren't useful
-grows HAIR! hypertrichosis |
|
|
what is considered a HTN emergency?
|
when DBP is over 150 or SBP is over 210.
|
|
|
drugs used for HTN emergencies?
|
Sodium nitroprusside
Labetalol Fenoldopam Nicardipine |
|
|
how does nitroprusside work? administration? adverse effects/
|
reduces cardiac preload but acting on veins. IV. Cyanide toxicity is rare but can be treated with sodium thiosulfate.
POISON if given orally |
|
|
what does Labetalol work on? Administration? what is different about its adverse effects?
|
works on alpha and beta receptors. IV bolus
Does NOT cause reflex tachycardia |
|
|
what is fenoldopam? administration?
|
peripheral dopamine-1 receptor agonist
IV infusion |
|
|
how does fenoldopam work?
|
maintains renal perfusion but lowers BP.
|
|
|
when should you especially use fenoldopam in a HTN emergency?
|
in Pts with renal insufficiency
|
|
|
What is nicardipine?
|
Ca channel blocker used for HTN emergencies
|
|
|
how is nicardipine administered?
|
IV infusion
|
