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