Step 1 - Micro 7

denniskwinn's version from 2015-04-25 16:10

Drug mechanisms

Question Answer
Penicillin mechanism1. Bind PBPs 2. Block transpeptidase cross-linking of cell wall 3. Activate autolytic enzymes
Aminopenicillins mechanismsame as penicillin, wider spectrum: penicillinase sensitive
Antipseudomonals mechanismSame as penicillin - extended spectrum
Cephalosporins mechanism Beta lactam drugs that inhibit cell wall synthesis but are less susceptible penicillinases (bactericidal)
Aztreonam mechanismMonobactam - resistant beta lactamases - synergistic with aminoglycosides - no cross allergenicity with penicillins
Imipenem/cilastatin, meropenem mechanismbroad-spectrum carbapenem (beta lactam) - beta lactamase resistant - always administer with cilastatin decrease incactivation in renal tubules
Vancomycin mechanismInhibit cell wall mucopeptide formation -Bactericidal - resistance w/change of D-ala D ala D-ala D lac
Aminoglycosides MechanismCidal - block formation of initiation complex - cause mRNA misreading - require O2 for uptake
Tetracycline mechanismsBacteriostatic - bind 30S prevent t-RNA attachment - doxycycline is fecally eliminated and can be used in pts with renal failure - - must not take with milk, antacids or iron-containing preparations = will inhibit absorption
Macrolides mechanisminhibit protein synthesis by blocking translocation - Bacteriostatic
Chloramphenicol mechanismInhibits 50S peptidyltransferase activity - bacteriostatic
Clindamycin mechanismblocks peptide bond formation at 50S - bacteriostatic
Trimethprim mechanisminhibits bacterial dihydrofolate reductase - static
Fluoroquionolone mechanismInhibit DNA gyrase (poisomeraseII) - bactericidal (must not be taken with antacids)
Metronidazole mechanismforms toxic metabolites in bacterial cell that damage DNA. Bactericidal, antiprotozoal.
Polymyxin mechanismBind cell membranes of bacteria and disrupt osmotic properties. Cationic basic proteins that act like detergents
Isoniazid (INH) mechanismdecrease synthesis of mycloic acids
Rifampin mechanismInhibits DNA-dependent RNA polymerase
Amphotericin B mechanismbinds ergosterol (unique fungi); forms membrane pores that allow leakage of electrolytes
Nystatin mechanismbinds ergosterol disrupting fungal membranes - too toxic for system use.
Interferons mechanism glycoproteins from human leukocytes that block various stages of viral RNA and DNA synthesis. Induce ribonuclease that degrades viral mRNA
Fusion inhibitors mechanismbind viral gp41 subunit; inhibit conformational change required for fusion with CD4 cells. Therefore block entry and subsequent replication.
Reverse transcriptase inhibitor mechanismPreferentially inhibit RT of HIV - prevent incorporation of DNA copy of viral genome in host DNA
HIV protease inhibitors mechanismInhibit maturation of new virus by blocking protease in progeny virions
Foscarnet mechanismViral DNA polymerase inhibitor - binds pyrophosphate-binding site of enzyme. Does not require activation by viral kinase.
Ganciclovir mechanism5’-monophosphate formed by a CMV viral kinase or HSV/VZV thymidine kinase. Guanosine analog. Triphosphate formed by cellular kinases. Preferentially inhibits viral DNA polymerase.
Acyclovir mechanismMonophosphorylated by HSV/VZV thymidine kinase - preferentially inhibits viral DNA polymerase by chain termination
Ribavirin mechanismInhibits synthesis of guanine nucleotides by competitively inhibiting IMP dehydrogenase.
Zanamivir, Oseltavir mechanismInhibit influenza neuraminidase, decreasing the release of progeny virus
Amantadine mechanismblocks viral penetration/uncoating (M2 protein) may buffer pH of endosome. (A man dine takes off his coat) Also causes the release of dopamine from intact nerve terminals
Griseofulvin mechanisminterferes with microtubule function; disrupts mitosis. Deposits in keratin-containing tissues (nails)
Terbinafine mechanisminhibits the fungal enzyme squalene epoxidase
Capsofungin mechanismInhibit cell wall synthesis by inhibiting synthesis of B-glucan
Flucytosine mechanismINhibits DNA synthesis by conversion 5-fluorouracil
Azole mechanisminhibit fungal sterol (ergosterol) synthesis
Sulfonamide mechanismdihydropteroate synthetase inhibitor (blocks folate synthesis)


Question Answer
Mechanism of Aminoglycoside resistanceModification of acetylation, adenylation or phosphorylation
Mechanism of Vancomycin resistanceTerminal d-ala replaced with d-lac decreased affinity
Mechanism of Chloramphenicol resistanceModification via acetylation
Mechanism of Macrolide resistanceMethylation of rRNA near erythromycin’s ribosome binding site
Mechanism of tetracycline resistancedecreases uptake, increased transport out of cell
Mechanism of Sulfonamide resistanceAltered enzyme, decreased uptake, or increased PABA synthesis
Mechanism of Quinolone resistanceAltered gyrase or reduced uptake
Amantidine mechanism of resistanceMutated M2 protein - 90% of all influenza A strains are resistant
Acyclovir mechanism of resistancelack of thymidine kinase in the virus
Ganciclovir mechanism of resistanceMutated CMV DNA polymerase or lack of viral kinase
Foscarnet mechanism of resistanceMutated DNA polymerase

Drug names, etc


Question Answer
Penicillinase resistant penicillinsMethicillin, Nafcillin, Dicloxacillin
AminopenicillinsAmpicillin, amoxicillin
AntipseudomonalsTicarcillin, carbenicillin, peperacillin
First generation cephalosporins names and use1. Cefazolin, cephalexin 2. Gram + cocci, proteus mirabilis, e. Coli, klebsiella pneumoniae (PEcK)
Second generation cephalosporins names and uses1. Cefoxitin, Cefacr, Cefuroxime 2. HEN PEcKS ( Haemophilus influenzae, Enterobacter acrogenes, Neisseria spp., Proteus mirabilis, E. Coli, Klebsiella pneumoniae, Serratia marcescens
Third generation cephalosporins names and uses1. Ceftriaxone, Cefotaxime, Ceftazidime 2. Serious gram - infections resistant other beta lactams - meningitis 3. Most penetrate the BBB
4th generation cephalosporins name and usesCefepime - increased activity vs Pseudomonas and gram + organisms
50S inhibitorsCELL (Chloramphenicol, Clindamycin (static)) (Erythromycin (static)) (Lincomycin (static)) (Linezolid (variable)
AminoglycosidesGentamicin, Neomycin, Amikacin, tobramycin, Streptomycin (GNATS)
TetracyclinesTetracycline, doxycycline, democlocycline, minocycline
MacrolidesErythromycin, azithromycin, clarithromycin
SulfonamidesSulfamethoxazole (SMX), sulfisoxazole, sulfadiiazine
FluoroquinolonesCiprofloxacin, Norfloxacin, Ofloxacin, Sparfloxacin, Moxifloxacin,Gatifloxacin, Enoxacin, and Nalidixic acid(a quinolone) (CON MEN SG)
PolymyxinsPolymyxin B and E
HIV protease inhibitorsSaquinavir, rinavir, indinavir, nelfinavir, amprenavir (RAINS)
HIV Nucleoside ( RT inhibitors)didanosine (ddl), zalcitabine (ddC), Zidovudine (ZDV, formerly AZT), stavudine(d4t), lamivudine (3TC), abacavir
HIV non nucleoside RT inhibitorsNevirapine, Efavirenz, Delavirdine
AzolesFluconazole, keconazole, clotrimazole, miconazole, itraconazole, voriconazole


Question Answer
Prophylaxis for M. TuberculosisIsoniazid
Treatment for M. TuberculosisRIPE (Rifampin, Isoniazid, Pyrazinamide, Ethambul)
Prophylaxis for M. Avium-intracellulareAzithromycin
Treatment for M. Avium-intracellulareAzithromycin, rifampin, ethambul, strepmycin
Treatment for M. LepraeDapsone, Rifampin, Clofazimine
Anit-TB drugs(SPIRE) Strepmycin, Pyrazinamide, Isoniazid, Rifampin, Ethambutol ... Cycloserine is second line therapy.
Ethambutol side effectsOptic neuropathy (red green color blindness)
Meningococcal infection prophylaxisRifampin, minocycline
Gonorrhea prophylaxisCeftriaxone
Syphilis prophylaxisBenzathine penicillin G
Prophylaxis for recurrent UTIsTMP-SMX
Prophylaxis for pneumocystis jiroveci pneumoniaTMP-SMX (drug of choice) , aerosolized pentamidine
Prophylaxis for endocarditis post surgPenicillins
Treamtent of MRSA vancomycin
Treatment of VRELinezolid and strepgramins (quinipristin/dalfopristin)
HAARTHighly active antiretroviral therapy -combination therapy with protease inhibitors and reverse transcriptase inhibitors - initiated when patients have low CD4 counts (<500) or high viral load. ZDV is used for general prophylaxis and during pregnancy reduce risk of fetal transmission
HIV fusion inhibitorsEnfuvirtide
Antibiotics avoid in pregnancySAFE Moms Take Really Good Care (Sulfonamides -kernicterus, Aminoglycosides - otoxicity, Fluoroquinolones - cartilage damage, Erythromycin - acute cholestatic hepatitis in mom, Metronidazole, Tetracyclines - discolored teeth, inhibition of bone growth, Ribavirin (antiviral) - teragenic, Griseofulvin (antifungal) -teragenic, Chloramphenicol -gray baby)
Drugs that block cell wall synthesis by inhibition of peptidoglycan cross-linking (Penicillin, ampicillin, ticarcillin, piperacillin, imipenem, atreonam, cephalosporins
Drugs that block peptidoglycan synthesisBactitracin, vancomycin
Drugs that disrupt bacterial cell membranesPolymyxins
Drugs that block nucleotide synthesisSulfonamides, trimethoprim
Drugs that block DNA topoisomerasesFluoroquinolones
Drugs that block mRNA synthesis Rifampin
Drugs that block 50S ribosomal subunitChloramphenicol, macrolides, clinamycin, strepgramins (quinupristin, dalfopristin), linezolid
Drugs that block 30s ribosomal subunitAminoglycosides, tetracyclines
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Bacteriostatic antibiotics(ECSTaTiC about bacteriostatic) Erythromycin, Clindamycin, Sulfamethoxazole, Trimethoprim, Tetracyclines, Chloramphenicol
Bactericidal antibiotics(Very Finely Proficient At Cell Murder) - Vancomycin, Fluoroquinolones, Penicillin, Aminoglycosides, Cephalosporins, Metronidazole
Forms of penicillinG(IV form), V(oral),
30 S inhibitorsAT (Aminoglycosides = strepmycin, gentamicin, bramycin, amikacin = cidal) (Tetracyclines = static)