Droogs - Antibiotics

bananas's version from 2015-05-26 18:33


Question Answer
Treats TBRIPE:
When is Rifampin used in monotherapy?Prophylaxis with H. influenza or N. meningitidis
Turns urine orange?Rifampin (Often described as blood in the urine)
EthambutolInhibits arabinosyl transferase(polymerizes carbohydrates)
Inhibiting arabinogalactan synthesis


Question Answer
Inhibit cell wall synthesis -- peptidoglycan cross-linkingPenicillin
Aminopenicillins: Ampicillin, Amoxicillin
Antipseudomonals: Piperacillin, Ticarcillin
Carbapenem: Imipenem
Monobactams: Aztreonam
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, streptogramins (quinupristin, dalfopristin), linezolid
Drugs that block 30s ribosomal subunitAminoglycosides, tetracyclines
Make drawing on 184184


Question Answer
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

Beta-lactam antibiotics (Penicillin --> prototype Beta-lactam ABx's)

Question Answer
Forms of penicillinG (IV form), V (oral),
Penicillin mechanism1. Bind PBPs 2. Block transpeptidase cross-linking of cell wall 3. Activate autolytic enzymes
Penicillin clinical use1. Bactericidal for gram + cocci, rods, gram - cocci and spirochetes
Penicillin toxicityHypersensitivity reactions, hemolytic anemia
Penicillinase resistant penicillinsMethicillin, Nafcillin, Dicloxacillin
Penicillinase resistant penicillin clinical usesS. Aureus (except MRSA; resistant because of altered penicillin-binding protein target site)
Penicillinase resistant penicillins toxicityhypersensiticity rxns; methicillin - interstitial nephritis
AminopenicillinsAmpicillin, amoxicillin
Aminopenicillins mechanismsame as penicillin, wider spectrum: penicillinase sensitive *** Combine with clavulanic acid (penicillinase inhibitor) to enhance spectrum, like Augmentin
Aminopenicillin clinical usegram+, gram-rods...1. HELPS ( H. Flu, E. Coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, enterococci)
Aminopenicillin toxicityHypersensitivity reactions: ampicillin rash; pseudomembranous colitis
AntipseudomonalsTicarcillin, carbenicillin, peperacillin
Antipseudomonals mechanismSame as penicillin - extended spectrum
Antipseudomonals clinical usePseudomonas spp. and gram-negative rods; susceptible to penicillinase; use with clavulanic acid (beta-lactamase inhibitor)
Antipseudomonals toxicityhypersensitivity reactions
Cephalosporins mechanism Beta lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases (bactericidal)
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, Cefactor, Cefuroxime 2. HEN PEcKS ( Haemophilus influenzae, Enterobacter aerogenes, Neisseria spp., Proteus mirabilis, E. Coli, Klebsiella pneumoniae, Serratia marcescens
Third generation cephalosporins names and uses1. Ceftriaxone, Cefotaxime, Ceftazidime 2. Serious gram - infections resistant to other beta lactams - meningitis 3. Most penetrate the BBB
4th generation cephalosporins name and usesCefepime - increased activity vs Pseudomonas and gram + organisms
Cephalosporin toxicitiesHypersensitivity reactions - cross hypersensitivity with penicillins occur in 5-10% of patients. Increases nephrotoxicity of aminoglycosides; disulfiram-like reaction with ethanol; some cause vit-K deficiency
Aztreonam mechanismMonobactam resistant to beta-lactamases - synergistic with aminoglycosides - no cross allergenicity with penicillins
Aztreonam clinical use Gram neg rods, like Klebsiella, Pseudomonas, Serratia, No activity against gram+ or anaerobes. For penicillin allergic patients and those with renal insufficiency who cannot tolerate aminoglycosides
Aztreonam toxicityUsually nontoxic, occasional GI upset - no cross sensitivity with penicillins or cephalosporins
Imipenem/cilastatin, meropenem mechanismbroad-spectrum carbapenem - beta lactamase resistint - always administer with cilastatin to decrease incactivation in renal tubules "LASTIN w ciLASTATIN"
Imipenem clinical useGram+cocci, gram - rods, anaerobes. DOC for enterobacter but significant side effects limit to life-threatening infections. Meropenem has reduced risk of seizures and stable to diydropeptidase I.
Imipenem toxicityGI distress, skin rash, CNS toxicity (seizures) at high plasma levels

Other bactericidal Abx

Question Answer
Vancomycin mechanismInhibit cell wall mucopeptide formation -Bactericidal - resistance w/change of D-ala D ala to D-ala D lac
Vancomycin clinical use Serious gram+ multidrug resistant organisms (S. Aureus, C.diff)
Vancomycin toxicityNephrotoxicity, Ototoxicity, Thrombophlebitis, diffuse flushing - “red man syndrome” (can prevent by pretreatment antihistamines and slow infusion rate) well tolerated in general
30 S inhibitorsAT (Aminoglycosides = streptomycin, gentamicin, tobramycin, amikacin = cidal) (Tetracyclines = static)
50S inhibitorsCELL (Chloramphenicol, Clindamycin (static)) (Erythromycin (static)) (Lincomycin (static)) (Linezolid (variable))
AminoglycosidesGentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin (GNATS)
Aminoglycosides MechanismCidal - block formation of initiation complex (30s inhibitor) - cause mRNA misreading - require O2 for uptake
Aminoglycosides clinical useSevere gram - rod infections, synergystic with beta-lactams - Neomycin for bowel surgery - ineffective against anaerobes
Aminoglycosides ToxicityNephrotoxicity (especially when used with cephalosporins), Ototoxicity (especially when used with loop diuretics), Teratogen
FluoroquinolonesCiprofloxacin, Norfloxacin, Ofloxacin, Sparfloxacin, Moxifloxacin,Gatifloxacin, Enoxacin (fluoroquinolones) and Nalidixic acid (a quinolone)
Fluoroquionolone mechanismInhibit DNA gyrase (topoisomerase II) - bactericidal (must not be taken with antacids)
Fluoroquinolones clinical useGram - rods of urinary and GI tracts (including pseudomonas), Neisseria, some gram +
Fluoroquinolones ToxicityGI upset, superinfection, skin rashes, headache, dizziness. Contraindicated in pregnant women and children b/c of potential cartilage damage. Tendonitis and tendon rupture in adults, leg cramps and myalgias in kids
Metronidazole mechanismforms toxic metabolites in bacterial cell that damage DNA. Bactericidal, antiprotozoal.
Metronidazole clinical useTreats Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, anaerobes (bacteroides, clostridium) - Used with bismuth and amoxicillin (or tetracycline) for triple therapy against H.pylori
Metronidazole toxicity Disulfram like reaction with alcohol; headache, metallic taste

Bacteriostatic Abx

Question Answer
TetracyclinesTetracycline, doxycycline, democlocycline, minocycline
Demeclocycline clinical useADH antagonist - SIADH tx
Tetracycline mechanismsBacteriostatic - bind to 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
Tetracycline clinical usesVACUUM THe BedRoom (Vibrio cholerae, Acne, Chlamydia, Ureaplasma, Urealyticum, Mycoplasma pneumoniae, Tularemia, H.pylori, Borrelia burgdorfia (lyme), Rickettsia
Tetracycline ToxicityGI distress, discoloration of teeth and inhibition of bone growth in children, photosensitvitiy - contraindicated in pregnancy
MacrolidesErythromycin, azithromycin, clarithromycin
Macrolides mechanisminhibit protein synthesis by blocking translocatoin - Bacteriostatic
Macrolides clinical useURIs, pneumonias, STDs - gram + cocci (streptococcal infections in patients allergic to penicillin), mycoplasma, legionella, chlamydia, neisseria
Macrolide toxicityProlonged QT (esp erythro), GI discomfort, acute cholestatic hepatitis, eosinophilia, skin rashes, Increases serum concentration of theophyllines, oral anticoagulants
Chloramphenicol mechanismInhibits 50S peptidyltransferase activity - bacteriostatic
Chloramphenicol clinical useMeningitis (H. Flu, N. Meningitidis, Strep pneumo) - conservative use due to toxicities
Chloramphenicol toxicitiesAnemia (dose dependent), aplastic anemia, gray baby syndrome (in premature infants because they lack liver UDP-glucuronyl transferase
Clindamycin mechanismblocks peptide bond formation at 50S - bacteriostatic
Clindamycin clinical useTreat anaerobes above the diaphragm - (Bacteroides fragilis, Clostridium perfringens)
Clindamycin toxicityPseudomembranous colitis (C.diff overgrowth) , fever, diarrhea
SulfonamidesSulfamethoxazole (SMX), sulfisoxazole, sulfadiiazine
Sulfonamides clinical useGram +, Gram - , Nocardia, Chlamydia, Triple sulfas or SMX for simple UTI
Sulfonamides ToxicityHypersensitivity, hemolysis if G6PD deficient, nephrotoxicity, photosensitivity, kernicterus in infants, displace other drugs from albumin (warfarin)
Trimethprim mechanisminhibits bacterial dihydrofolate reductase - static
Trimethoprim clinical usein combination with sulfonamides causing sequential block of folate synthesis - combination used for recurrent UTI, shigella, salmonella, pneumocystis jiroveci pneumonia
Trimethoprim toxicityMegaloblastic anemia, leukopenia, granulocytopenia (may alleviate with supplemental folic acid) "TMP - treats marrow poorly"
Sulfa drug allergies patients who do not tolerate sulfa dugs should not be given sulfonamides or other sulfa drugs, such as sulfasalazine, sulfonylureas, thiazide diuretics, acetazolamide or furosemide
PolymyxinsPolymyxin B and E
Polymyxin mechanismBind to cell membranes of bacteria and disrupt osmotic properties. Cationic basic proteins that act like detergents
Polymyxin clinical useResistant gram - infections
Polymyxin toxicityNeurotoxicity, acute renal tubular necrosis


Question Answer
Prophylaxis for M. TuberculosisIsoniazid
Treatment for M. TuberculosisRIPE (Rifampin, Isoniazid, Pyrazinamide, Ethambutol)
Prophylaxis for M. Avium-intracellulareAzithromycin
Treatment for M. Avium-intracellulareAzithromycin, rifampin, ethambutol, streptomycin
Treatment for M. LepraeDapsone, Rifampin, Clofazimine
Anit-TB drugs(SPIRE) Streptomycin, Pyrazinamide, Isoniazid, Rifampin, Ethambutol ... Cycloserine is second line therapy.
Ethambutol side effectsOptic neuropathy (red green color blindness)
Isoniazid (INH) mechanismdecrease synthesis of mycloic acids
Isoniazid clinical useMycobacterium tuberculosis - solo prophylaxis
Isoniazid toxicityNeurotoxicity, hepatotoxicity, pyridoxine (B6) can prevent neurotoxicity
Rifampin mechanismInhibits DNA-dependent RNA polymerase
Rifampin clinical use Mycobacterium tuberculosis - delays resistance to dapsone when used for leprosy. Used for meningococcal prophylaxis and chemo prophylaxis in contacts of children with H. Flu B. - rapid resistance if monotherapy
Rifampin toxicityMinor hepatotoxicity and drug interactions (increased p450) - orange body fluids (nonhazardous)


Question Answer
Mechanism of penicillin/cephalosporin resistanceBeta-lactamase cleavage of beta-lactam ring or altered PBP in caes of MRSA or penicillin resistant S. Pneumoniae
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


Question Answer
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 streptogramins (quinipristin/dalfopristin)