Anti-Microbial Drugs I Flashcards
All aminoglycosides concentrate in:
Renal cortex
Spectrum of the aminoglycosides:
More Gram (-) rods Some Gram (+) cocci
Aminoglycosides are DOC for:
Enterobacter E. coli K. pneumonia Proteus Serratia P. aeruginosa
“mycin” drugs are derived from:
Streptomyces
“micin” drugs are derived from:
Micromonospora
Once a day dosing is effective if the drug has:
Significant post-antibiotic effect
Concentration dependent killing
Most stable aminoglycoside against R-plasmid enzymes?
Amikacin
Most vesitbulotoxic aminoglycosides:
Streptomycin
Gentamycin
Most hearing toxic aminoglycosides:
Neomycin
Kanamycin
Amikacin
Most nephrotoxic aminoglycosides:
Neomycin
Tobramycin
Gentamycin
Aminoglycosides must not be used with __ due to its __ effects
Neuromuscular blockers; neurotoxic
Penicillins bind to PBPs at the ___ terminal and inhibit the ___ enzyme.
d-ala-d-ala; transpeptidase
Exceptions to renal clearance of PCNs:
Naficillin (biliary)
Oxacillin, Cloxacillin, Dicloxacillin (biliary and renal)
This drug inhibits secretion of PCN:
Probenecid
Nafcillin is not as nephrotoxic as other PCN but may cause:
neutropenia
Most active PCN against pneumococci:
Aminopenicillins
Extended spectrum penicillins are combined with ___ to achieve synergistic effect:
aminoglycoside
Cephalosporins are NOT active against:
L-monocytogenes
Atypicals
MRSA
Enterococci
Cephalosporins excreted through bile:
Cefamandole
Cefoperazone
Ceftriaxone
Cephalosporins with disulfiram-like effectsL
Cefamandole
Cefoperazone
Moxalactam
Only first generation Cephalosporin still in use:
Cefazolin
2nd Gen Ceph used against community acquired pneumonia:
Cefuroxime
More effective than Cefuroxime in crossing the BBB:
3rd Gen:
Ceftriaxone
Ceftaxime
2nd Gen Ceph active against Bacteriodes:
Cefoxitin
2nd Gen Ceph more susceptible to beta-lactamase:
Cefaclor
2nd Gen Ceph active against H. influenzae:
Cefmandole
Cefuroxime
Cefaclor
Only 3rd Gen Ceph that cannot cross the BBB:
Cefoperazone
Only 3rd Gen Ceph with activity against Gram (+):
Cefotaxime
Ceftriaxone is effective against:
Resistant salmonella typhi
Gonorrhea
3rd Gen Ceph more active against pseudomonas:
Ceftazidime (+ cefoperazone)
3rd Gen Ceph with more activity against anaerobes:
Ceftizoxime (+ moxolactam)
Ceftriaxone and Cefotaxime are effective against:
Meningitis due to pneumococci, meningococci, h. influenza
For neutropenic, febrile, immunocompromised patient:
Ceftazidime+ antibiotic
4th Gen Cephalosporin:
Cefepime
Aztreonam is only active against:
Gram (-) rods (including pseudomonas)
Absorption of aztreonam:
IV only, not absorbed orally
Advantages of Aztreonam:
Not nephrotoxic
“cidal” under anaerobic conditions
No PCN cross allergenicity
Carbapenem only active against intracellular bacteria:
Imipenem
This carbapenem is more often used and is more active against:
Meropenem; Enterobacteria and p. aeruginosa
Carbapenems bind to these PBPs preferentially, leading to rapid lysis:
PBP-1 “steady”
PBP-2 “moving”
Imipenem is combined with this drug to increase it’s half-life:
Cilastatin (inhibitor of renal dihydropeptidase)
Beta-lactamase inhibitors:
Clavulanic Acid
Sulbactam
Tazobactam
Lack of ____ in neonates leads to this adverse reaction:
hepatic glucoronosyltransferase (glucoronic acid); Gray baby syndrome
Dose dependent adverse reaction to chloramphenicol:
Aplastic anemia
Chloramphenicols are an alternate drug for ____ and ineffective against ____.
Pneumonia; chlamydia
Chloramphenicols have an antagonistic effect with:
Aminoglycosides and Penicillins (-cidal drugs)
Lincosamides inhibit protein synthesis by binding to:
23s portion of 50s subunit
Lincosamides are active against ___, except for:
Gram (+) cocci, anaerobes;
Not active against: Staph, strep, enterococcus
Drug associated with pseudomembranous colitis:
Clindamycin
Excretion of lincosamides:
Biliary and renal
Lincosamides have good penetration in ___, but not in:
Bone, fibrous CT, alveolar macrophages;
no penetration in CNS
Clinical uses for Lincosamides:
Acne Osteomylitis Pneumocystis carinii Toxoplasmosis gondii Prophylaxis for valvular diseases
DOC against clostridium dificile:
Metronidazole (also amoeba organisms)
Spectrum of Macrolides:
Gram (+) aerobes
Some gram (-) aerobes (DOC for legionella)
Atypicals
Macrolide excreted in bile and feces:
Erythromycin (renal failure no problem)
Macrolide excreted in liver and kidneys:
Clarithromycin
Macrolide excreted slowly in urine, unchanged:
Azithromycin
Macrolide with high distribution in tissues and phagocytes vs. plasma:
Azithromycin
This drug is used in treatment of gastroparesis by binding to:
Erythromycin; motilin receptors
This macrolide is CI in pregnant women due to risk of ___.
Erythromycin estolate; acute cholestatic hepatitis
Absorption of erythromycin is mainly in the:
Duodenum (impeded by food)
Best absorbed erythromycin:
estolate salt
Erythromycin and CYP3A inhibitors increase the risk of:
Cardiac arrhythmia
Co-administration of these drugs with erythromycin should be avoided by those with heart abnormalities:
Diltiazem or verapamil
Reasons for telithromycin (ketolide) effectiveness against resistant strains:
Poor substrate for efflux pump
Higher affinity for ribosomes
MOA of polymixin:
Disrupt bacterial cell membranes
Bind and activate endotoxin
Adverse effects of polymixin:
Substantial nephrotoxicity
Substantial neurotoxicity
(no longer used systematically)
First oral anti-pseudomonal drug:
Quinolones
MOA of Quinolones?
Inhibit DNA gyrase (topo II and topo IV)
Quinolones more active against p.aeruginosa:
Ciproflaxin
Quinolones active against staphylococci:
Fluoroquinolones
Quinolones active against streptococci:
Levofloxacin and Moxifloxacin
Inhibitors of folic acid synthesis:
Sulfonamides (dihydropteroate synthetase)
Diaminopyrimidines (dihydrofolate reductase)
Tetracyclines have excellent activity against:
Mycoplasma pneumonia
Chlamydia trachomatis
Tetracyclines have good activity against:
Gram (+), e. coli, klebsiella
Tetracyclines have minimal activity against:
anaerobes
Primary indications of tetracycline:
Mycoplasma Chlamydia Rickettsia Vibrios Borrelia
Secondary indications of tetracyclines:
Syphilis
Respiratory infection
Leptospirosis
acne
Most tetracyclines are excreted ___, except for:
Renally; Doxycycline (liver)
Tetracylcine affinity for ____ is responsible for it’s effect of:
Chelators (calcium, iron, aluminum); enamel dysplasia (mottling of teeth)
Adverse reactions of tetracycline:
Hepatotoxicity
Nephrotoxicity (Fanconi like syndrome)
Photosensitivity
Vestibular toxicity
Vancomycin is a ___ and so does not cross the BBB:
Glycopeptide
Red man syndrome is associated with:
Type I hypersensitivity caused by Vancomycin
2 streptogamins in a ____ ratio that interact ___:
Dalfopristin (Streptogamin A) and Quinipristin (Streptogamin B); 70:30 ratio; synergystically
Excretion of vancomycin is completely:
Renal (problem in renal patients)
Resistance to streptogamins is due to modification of the ___ site:
quinipristin
Spectrum of streptogamins:
Gram (+) cocci (including drug resistant)
Oxazolidinones have a unique __ binding site:
23s
Oxazolidinones are primarily static, but bactericidal for:
Streptococci
Most common adverse reaction to oxazolidinones:
Thrombocytopenia
Inhibits very early stage of bacterial wall synthesis:
Fosfomycin
These drugs act only in the urinary bladder, not systemically:
Nitrofurantoin (except p. aeruginosa & proteus) Methenamine hippurate (except proteus) Phenazopyridine (analgesic only)
MOA of daptomycin:
Disruption of cytoplasmic membrane
Daptomycin is effective against ___ but not against ___.
Staphylococcus; respiratory infections
Bacteriostatic activity against MRSA:
Tigecycline
