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45 Cards in this Set

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What are penicillins and Cephlasporins Classified as what do they do and how safe are they?
Classified as Beta lactmas, they inhibit cell wall synthesis/peptidoglycan syntheis and are the safest drugs in terms of toxicity
What other drugs inhibit cell wall synthesis?
VANCOMYCIN, Isoniazid, Ethanbutol, Cycloserin, Ethionamide, Bacitracin, Polymycin
What can coupling aminoglycosides and penicillin together do?
Drug combo can have more side effects than penicillin alone
What are the key structures of Penicillin?
Beta-Lactam Ring
Thiazolidine ring, lacking in other B-Lactams
R group; differentiates classes of penicillin
What is Penicillinase/B-Lactamase, how does it work, and is their any clinical importance?
Produced by bacteria (+) and cause the resistance to beta-lactam ABX
Works by breaking the ring open and deactivating the drug
Can be given to protect normal flora during ABX treatment
What is the mechanism of action for Penicillin and Cephlasporin?
Bind/inhibits PBP (penicillin-binding-protein) which inactivates bacterial transpeptidase enzymes required for cell wall synthesis
Eventually causing cell lysis
Which is more resistant to B-Lactamase, Cephlasporins or Penicillin?
Cephlasporins
What are two other ways of bacterial resistance?
Bacterial modification of PBP which will alter binding to the drugs
Drug efflux pump which pumps the drug out through porins
What is Probenecid (Benemid)?
A drug that increases the bioavailability of Penicillin in the body
Also been used as a masking agent for drugs in Pro-Athletes
What drugs are not effective against Gram Negative Bacteria and why?
1 and 2 generation penicillins because of their hydrophobic structure
How do drugs enter Gram (+) and Gram (-) bacteria
Gram (+) by way of diffusion and Gram (-) via porins
Pharmokinetics of Penicillin G (1st generation)
Low bioavailability
Short half life
Low penetration to CNS
What does Pennicillin G do?
Narrow spectrum of action
Treats Staph, Strep, Lyme, and Bacillus (Anthrax)
Difficulty with Gram (-) rods
What are Antistaphylococcal Drugs, what do they do, and what is an example?
Class of 1st generation which treats Staphylococcal that are penicillin resistant; i.e. produce B-Lactamase
Ex: Nafcillin, Dicloxacillin, and Methicillin (what MRSA is resistant too)
What are the names of the 2nd generation Penicillins?
Aminopenicillins: Specifically
Ampicillin and Amoxicillin
What are the advantages and disadvantages to 2nd generation Penicillins?
More reliable oral bioavailability, Same spectrum of Gram (+) but also can fight some Gram (-)
NOT suitable for Pseudomonas
NOT resistant to B-Lactamases
What are the third generation penicillins and some features of them?
Antipseudomonal: Ticarcillin (Tigar) (poor oral absorbtion) and Carbenicillin (UTI's only)
What are the main actions of the 3rd generation penicillins?
Mainly used for Gram (-) Pseudomonas, but NOT preferred for Gram (+)
Often combined with Aminoglycoside
NOT resistant to B-Lactamse inhibitors
What are the 4th generation penicillins?
Antipseudomonal: Piperacillin
What are the actions/adavantages Piperacillin, how is it administered, and what does it not have?
Broadest specturm of action of ALL penicillins
Super effective will "pepper and bug out" (+) or (-)
Requires parenteral admin.
Key is that it is effective against PSEUDOMONAS
NOT B-Lacatamase resistant
What is Piperacillin combined with sometimes and why?
Aminoglycosides to fight very serious Enterococci (endocarditis)
What are Beta-Lactamase inhibitors?
"Suicide molecules" that bind/inhibit lactamase enzymes
Used in combination therapy with penicillins
Ex: Clavulanic acid
What are two drugs that Clavulanic acid combines with
Amoxicillin and Clavulanic acid (Augmentin)
Ticarcillin and clavulanic acid (Timentin)
What is Imioenem and Aztreonam (Carbapenems)?
They are Broad Spec. Abx (NOT MRSA) used together
Strong resistance to B-Lactamase
Only given parenterally and used for pts who are allergic to penicillin
Monobactem (Aztreonam)
High affinity for Gram (-) PBP
Low affinity for Gram (+) PBP and Anaerobes
Good resistance to B-Lactamase and can be used in pts. that are allergic to penicillin
What type of drugs are mostly used for UTI's?
Quinolones
What is and causes Type I hypersensitivity?
Immediate rxns:1-72 hrs
Mediated by IgE antibodies
Can cause uticaria, angioedema and anaphylaxis
What is and causes Type II hypersensitivity?
Caused by cytotoxic antibodies of IgG
Hemolytic anemia
What is and causes Type III hypersensitivity?
Involve formation of immune complexes IgG or IgM
Serum sickness
What is and causes Type IV hypersensitivity?
Delayed rxns occuring after 72 hrs
Mediated by T lymphocytes
Contact dermatitis, rash
What do Cephalosporins do and when should they not be administered?
Inhibit cell wall synthesis bind to PBP, similar to Pens.
More resistant to B-Lacatamase
Can be good alternative to penicillin resistant lacatmase infections
DO NOT administer to pts who have previously had an immediate rxn to penicillin
How are Cephalosporins classifeid?
Spectrum of generations (1-4) dependent on Gram (-) activity
What are Cephlalosporins effective against?
Staphycoccal and Typhoid fever
What are the main differences between the 1-4 generation Cephalosporins?
Gradula decrease in Gram(+) effectivness and an Increase in Gram (-)
Also an increase in CNS penetration (3-4 are more lipid) and an increase in B-lactamase resistance
How does the Cephlosporins increse their lipid solubility?
Add aromatic rings and by 3rd generation have marked improvement in CSF penetration
How are Cephalosporins excreted and what does Probenecid do?
Excreted fairly unchanged in Urine
Probenecid slows secretion increasing bioavailibility
What are 1st generation Cephalosporins and when are they used?
Cefazolin
Only used for surgical prophylaxis
Gram (+) effectivness similar to 1st gen. Pens and Gram (-) effectivness similar to 2nd gen. Pens
What are none of the generation of Cephalosporins effective against?
Enterococci and MRSA
What are 2nd generation Cephalosporins effective against and what not?
Increased Gram (-) effectivness (P. Vulgasis & H. Influenzae) w/o compromising Gram (+) effectivness
NOT effective against Pseudomonas (key)
What are some 2nd generation Cephalosporins?
Cefaclor, Cefamandole, Cefoxitin, Cefotetan
What are 3rd generation Cephalosporins effective against and what not?
Decreased Gram (+) effectivness but good CNS penetration for treatment of Meningitis (e.g. strep)
What is Ceftriaxone used for and what generation?
3rd generation
Drug of choice for Gonorrhea
Main indication for Meningitis
Long Half Life compared to other B-Lactams
What are some other 3rd generation Cephalosporins?
Ceftazidime, Cefixime, Cefotaxime
Increased stability against Lacatamases, dont have to combine with B-Lactamase inhib
Name a 4th generation Cephalosporins and what is it effective against?
Cefepime
Most effective against B-Lactamase inhibitors and Gram(-)
Good activity against Enterobacteriaceae that are ristatn to 2 & 3
NO activity against Staph
What are the clinical indications for Cephalosporins?
Alternative to Pens. in penicillinase-producing bacteria
Surgic prophylaxis: Cefazolin Common gram (-) infections
Meningitis 3 Gen: Ceftriaxone
Otitis, Sinusitis, Upper and Lower Res. Infec.