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96 Cards in this Set
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Antimicrobials, Antiviral, and Antifungi Drugs
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We'll first start with general background on Antimicrobial drugs. (Ex: therapy, misuses, mode of action, delaying emergence, dosage, and host factors).
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__% of hospitalized patients receive drugs for infectious diseases. Chemotherapy, antibiotics, and antimicrobial agents are given.
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30%
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What is the difference between a narrow spectrum antibiotics and a broad spectrum antibiotic?
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Narrow spectrum antibiotics work on only a few species of microbes whereas Broad spectrum work on a large number of species.
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These drugs, other then chemotherapy, are able to target only bad organisms w/out harming cells or the host.
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It's based on the cell differences in microbes and host cells.
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There are quite a few ways for these drugs to eliminate or restrain the microbes (Mode of action). What are 6 MOA's and give an example of a drug for each.
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You can do it!
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1.) INHIBITION OF BACTERIAL CELL WALL SYNTHESIS OF ACTIVATION OF ENZYMES THAT DISRUPT THE CELL WALL
Include both broad and narrow spectrum antibacterial drugs that promote bacterial lysis & death (e.g. penicillins & cephalosporins) |
2.) INHIBITION OF BACTERIAL PROTEIN SYNTHESIS
May be bactericidal (e.g. gentamicin) or bacteriostatic (e.g. tetracyclines) |
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3.) INHIBIT SYNTHESIS OF BACTERIAL DNA AND RNA
Binds directly to nucleic acids or interact with enzymes required for nucleic acid synthesis (e.g. ciprofloxacin) |
4.) ANTIMETABOLITES
Interact with enzymes required for producing essential cellular metabolites (e.g. trimethoprim) |
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5.) INHIBITORS OF VIRAL ENZYMES (antiviral drugs)
Inhibit enzymes necessary for viral replication or infection; includes protease inhibitors and nucleoside analogs (e.g. zidovudine & indinavir) |
6.) INCREASE MEMBRANE PERMEABILITY (antifungal drugs)
Cause leakage of intracellular material (e.g. amphotericin B) |
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Microbe RESISTANCE!
Microbes can become resistant to drugs due to an alteration in active uptake of specific antibiotics, alterations in drug receptors, etc |
Microbe resistance in terms of DNA are due to spontaneous mutation or conjugation.
Bacteria are worse then Cancer cells in terms of resistance b/c they are faster at reproduction and are sloppy at it! |
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There are a few ways to DELAY EMERGENCE of drug resistance.
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Use these drugs only when needed.
Use narrow spectrum agents when can. Reserve newer antibiotics when older drugs are dangerous or aren't effective. |
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What does suprainfection mean?
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A new infection that appears during the course of treatment for a primary infection.
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Immunocompromised patients require bacteri_____ drugs.
IS it cidal or static? |
cidal
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These drug can cross placenta and breast milk.
True of false? |
True
Tetracyclines and fluoroquinolones contraindicated during pregnancy |
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Is it okay to stop taking these drugs if one feels better even before the date given by the physician?
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No
The patient must take the drug as long as the physician said too. Must not be discontinued prematurely. Why is that? |
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MISUSES
Attempt to treat an untreatable infection like the common cold or sore throat Fever come from an unknown organism |
MISUSES
Improper dosage Lack identification of organism Omission of surgical drainage |
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Now that we've talked about general information on these drugs...
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Let's talk that the drugs themselves!
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Drugs that weaken Bacterial Cell wall
The Penicillins, Cephalosporins, and Vancomycin. |
Let's start with the Penicillins...
Penicillin G Nafcillin Amoxicillin Carbenicillin |
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Penicillins
MOA: weaken cell wall which causes bacteria to take up excess water and causes it to BLOW UP! Well...Rupture. Is this drug a cidal or static drug? |
Cidal of course! This drug kills the bacteria!
Resistance to this drug: the drug never gets to it's target, the bacterial enzymes inactivate this drug. |
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Penicillins are not safe drugs.
True or false? |
FALSE!
Penicillins are among our SAFEST drugs! It is also the most common drug for people to be allergic too.. |
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Penicillin G [Benzylpenicillin]
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Penicillin G [Benzylpenicillin]
Narrow spectrum penicillinase sensitive Beats up: Streptococcus sp. Gram positive. Causes tetanus, gangrene, anthrax, syphilis. |
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Nafcillin [Nallpen]
(Methicillin no longer used in US) |
Nafcillin [Nallpen]
Narrow-spectrum penicillinase resistant Staphylococcus aureus |
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Amoxicillin [Amoxil]
and ampicillin [Marcillin] |
Amoxicillin [Amoxil]
Broad spectrum H. influenzae, E. coli, N. Gonorrhoeae Inactivated by beta lactamases, so not helpful for Staphylococcus |
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Carbenicillin [Geocillin]
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Carbenicillin [Geocillin]
Extended spectrum Same as broad-spectrum, plus UTIs Pseudomonas aeruginosa and others |
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Narrow spectrum penicillinase sensitive
Penicillin G comes in different forms Only K plus penicillin G is given IV. The rest are given IM |
Use of penicillinase inhibitor andbroad/extened spec pen
e.g. Clavulanic acid and amoxicillin [Augmentin] |
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Side Effects and Toxicities
Penicillin |
GI~ heartburn, diarrhea, stomatitis, discolored tongue
DDIs: Increased bleeding time of anticoagulants; Inactivate aminoglycosides if in same IV bag; Potentially decreased efficacy of oral contraceptives |
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Penicillin Allergy
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For one, you DON'T give a pt a drug if they are allergic to it.
This drug can cause anaphylaxis which has S/S of laryngeal edema, bronchoconstriction, and severe hypotention. Treat with Epiniphrine, respiratory support, and prevention |
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Cephalosporin
MOST WIDELY used group of antibiotics Bactericidal, beta-lactam antibiotics Usually given parenterally |
Mechanism of Action
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Cephalosporin
Altered PBPs ~ Mechanism of Action Bind PBPs (same as penicillin) |
Methicillin resistant staphylococcus resistant to most cephalosporins
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Adverse effects Cephalosporin
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Adverse effects Cephalosporin
Allergy (5 to 10% cross-rxn w/penicillins), bleeding (DDIs!), thrombophlebitis |
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Four generations of Cephalosporins
Each subsequent generation has greater...name 3 |
~activity against Gram negative bacteria
~resistance to beta lactamases ~ability to reach CSF |
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First generation ~
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Cephalexin [Keflex]
Used for staphylococcus if mild penicillin allergy |
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Third generation ~
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Cefotaxime [Calforan]
Meningitis and nosocomial infections resistant to others (restricted use) |
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Vancomycin [Vancocin]
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Ready?
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Action Vancomycin
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Action Vancomycin
Inhibitor of cell wall synthesis (like pens & cephs, however, vancomycin has no beta lactam ring, PBP binding, or penicillin allergy) |
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Uses (Restricted) Vancomycin
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Uses (Restricted) Vancomycin
Only for severe infections; Gram positive bacteria Methicillin resistant Staphylococcus aureus (MRSA), life threatening infection w/known susceptible organism in pt w/ severe allergy to penicillin, and Clostridium difficile colitis |
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Adverse effects Vancomycin
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Adverse effects Vancomycin
Ototoxicity (give over 60 min to limit) Allergic Rxn red neck syndrome ~ flushing, pruritus, tachycardia, hypotension Avoid by infusing slowly, lowers histamine release Thrombophlebitis |
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Bacteriostatic Inhibitors of Protein
You will know these 3 drugs... |
Tetracyclines
Erythromycin Linezolid |
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Tetracycline
Broad or Narrow Spectrum antibiotic? |
Broad Spectrum antibiotic
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Mechanism of Action Tetracycline
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Mechanism of Action:
Inhibits protein synthesis by binding to 30S ribosome, thus inhibiting mRNA/tRNA activity Bacteriostatic!! |
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Bacterial Resistance Tetracycline
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Bacterial Resistance Tetracycline
Reduced drug accumulation increased drug inactivation decreased access to ribosomes |
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Clinical Uses Tetracycline
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Clinical Uses Tetracycline
2nd line agent for resistant infections |
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Tetracycline 1st line Tx in
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1st line Tx in:
Rickettsial disease, Chlamydia trachomatis, Cholera, Mycoplasma pneumoniae, Lyme disease, Anthrax, Helicobacter pylori Acne PUD |
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Tetracyclines~Adverse Effects
There are quite a few but know the MAIN ONE which has to do with teeth... |
Adverse Effects:
Absorption~chelation Do NOT administer with anything with Ca, magnesium~containing laxatives, and most antacids |
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Tetracycline Adverse Effects:
Effect on bone and teeth (Ca2+ binding) ~ can suppress long bone growth in premature infants (is reversible) Avoid during pregnancy (Category D) & breastfeeding and in children <8 yo Photosensitivity Gastrointestinal (Admin w/ food) |
Tetracycline Adverse Effects:
Superinfection ~ C. difficile colitis Hepatotoxicity & Renal toxicity Decreased oral contraceptive efficacy & breakthrough bleeding |
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Inhibitors of Protein Synthesis:Macrolides ~
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Erythromycin [Erythrocin]
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Mechanism of Action Erythromycin
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Inhibits bacterial protein synthesis (binds to 50S ribosome)
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Resistance Erythromycin
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Develops from increased drug efflux and modification of ribosome
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Erythromycin Commonly used if...
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pt has severe penicillin allergy
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ErythromycinGenerally few SEs...
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GI (pain, nausea & vomiting, diarrhea)
DDIs! Avoid CYP3A4 inhibitors & antidysrhythmics due to cardiotoxicity |
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ErythromycinAntimicrobial spectrum
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Broad spectrum similar to penicillin;
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Erythromycin Uses
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Uses:
First choice for several infections (pneumonia caused by Legionella pneumophila, Bordetella pertussis, Corynebacterium diphtheriae) |
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Bacteriostatic Inhibitors of Protein Synthesis. Whats the 3rd one!?
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Linezolid [Zyvox]
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Has activity against VRE and MRSA. What do they stand for?
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multidrug resistant gram positive pathogens~ vancomycin resistant enterococci (VRE) and methicillin resistant Staphylococcus aureus (MRSA)
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Aminoglycosides: Bactericidal Inhibitors of Protein Synthesis. The 3 drugs prior to this one were bacterioSTATIC...
You'll just be learning one....which one is that now? |
Gentamycin [Garamycin]
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Gentamycin MoA
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Gentamycin MoA:
Severely disrupts bacterial protein synthesis (inhibition, AA termination, misreading) |
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GentamycinUse:
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GentamycinUse:
Serious infections caused by aerobic Gram negative bacilli (narrow spectrum) |
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Gentamycin Adverse effects
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Gentamycin Adverse effects:
Sig injury to inner ear and kidney (note high pitched tinnitus & headache) Neuromuscular blockade (respiratory depression) DDIs~(eg inactivated if in IV bag w/ Pen) |
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Gentamycin
Must be given parenterally b/c not absorbed True or False? |
True!
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Sulfamethoxazole
What are the two drugs you should know? |
Sulfonamides and Trimethoprim
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Suppresses bacterial growth by:
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Suppresses bacterial growth by inhibiting the synthesis of a DNA & RNA precursor (folic acid, aka folate)
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Sulfonamides and Trimethoprim Uses
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Uses
**Uncomplicated urinary tract infection (Escherichia coli) Pneumocystis carinii (common in immunocompromised hosts) |
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Sulfonamides and Trimethoprim Adverse effects
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Adverse effects:
Hypersensitivity reactions ***SEVERE is Stevens Johnson syndrome (low incidence, but 25% mortality) In peds and young adults; Major skin & mucous lesions, fever, malaise, toxemia |
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Adverse effects cont:
***Kernicterus (deposits of billirubin in brain) This drug is contradicted for who? |
Contraindicated for infants under 2 mo; during pregnancy (Category C) & breastfeeding
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Fluoroquinolones
What is the prototype? |
Ciprofloxacin [Cipro]
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Ciprofloxacin [Cipro]
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Broad spectrum antibiotic
Inhibits bacterial DNA gyrase (bactericidal) |
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Used for:
Most significant |
UTI and Anthrax
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Adverse effects:
Most significant |
CNS and tendon rupture
Candida of pharynx and vagina |
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Drug and food interactions
Ciprofloxacin [Cipro] |
Foods w/ cations (e.g. Ca2, Al, Mg2) will decrease drug absorption
Take on an empty stomach |
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So, those were all of you antimicrobials!...
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Let's review. What are the prototypes for the mode of actions?
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Inhibition of bacterial cell wall synthesis
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penicillins & cephalosporins
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Inhibition of bacterial protein synthesis
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bactericidal (e.g. gentamicin) or bacteriostatic (e.g. tetracyclines)
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Inhibit synthesis of bacterial DNA and RNA
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(e.g. ciprofloxacin)
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Antimetabolites
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(e.g. trimethoprim)
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We have Antiviral and Antifungi drugs left. For Antiviral drugs, you will be learning about...
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Antiviral:
Acyclovir Zidovudine [Retrovir] (AZT) Nevirapine [Viramune] Indinavir [Crixivan] |
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Drug for Non HIV Viral Infections
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Acyclovir [Zovirax]
Purine nucleoside analogs |
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Acyclovir Uses
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Herpes simplex viruses
Varicella zoster virus |
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Adverse effects based on route of administration
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IV ~ phlebitis and reversible nephrotoxicity
Oral therapy ~ GI and vertigo Topical ~ stinging sensations |
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Antiviral Agents II: Drugs for HIV Infection & Related Opportunistic Infections
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antiretroviral drugs
HIV fusion inhibitors Reverse transcriptase inhibitors: Nucleoside~ Zidovudine Nonnucleoside ~ Nevirapine Protease inhibitors: Indinavir |
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Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
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Zidovudine [Retrovir]
Inhibits HIV replication |
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Zidovudine Adverse effects
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Adverse effects:
Anemia Neutropenia Lactic acidosis Gastrointestinal effects CNS |
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Non Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
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Nevirapine [Viramune]
Binds to HIV reverse transcriptase |
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Nevirapine Adverse effects
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Adverse effects
Rash Erythema multiforme Stevens Johnson syndrome Hepatotoxicity Drug interactions |
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Protease Inhibitors
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Indinavir [Crixivan]
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Adverse Effects Indinavir
There QUITE a few. Ask Dr. Murphy if there are any that you NEED to know. |
Hyperglycemia/diabetes
Fat redistribution Hyperlipidemia Reduced bone density Hepatotoxicity Increased bleeding in hemophiliacs Reduced bone mineral density Elevation of serum transaminase Drug interactions |
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That is the end of antiviral drugs!
On to Antifungal agents!! What are the 4 drugs you will be learning? |
Amphotericin B [Fungizone]
Ketoconazole [Nizoral] Miconazole [Monistat] Nystatin [Mycostatin] |
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There are 2 major groups of antifungal drugs...
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Systemic mycotic infections
Superficial mycotic infections |
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Systemic mycotic infections
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Systemic mycotic infections
Opportunistic~candidiasis, aspergillosis, cryptococcosis, mucormycosis Nonopportunistic sporotrichosis, blastomycosis, histoplasmosis, coccidioidomycosis |
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Superficial mycotic infections
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Superficial mycotic infections
Candidiasis Dermatophytes |
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Amphotericin B [Fungizone]
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Broad spectrum antifungal, agent of choice
Highly toxic |
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MoA Amphotericin B
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MoA
Damages fungal cell membrane causing leakage of intracellular K |
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Uses: Amphotericin B
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Uses: systemic mycoses
Limit use to progressive and potentially fatal infections |
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Adverse effects Amphotericin B
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Adverse effects Amphotericin B
Infusion reactions Nephrotoxicity Hypokalemia |
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Ketoconazole [Nizoral]
Fungistatic |
Alternative to amphotecirin B for systemic mycoses
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Adverse effects Ketoconazole
Most Significant ones! |
Hepatotoxicity
Effect on sex hormones |
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Miconazole [Monistat]
Use~ |
vaginitis
Creams and vaginal inserts |
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Nystatin [Mycostatin]
Use ~ |
thrush (candidiasis)
If treating nursing baby, then treat mother (and vice versa) |