Antibiotics

Question 1

Definition: Concentration of abx needed to inhibit bacterial growth; lowest concentration of antibiotic that completely inhibits growth

Answer 1

Minimum inhibitory concenration

Question 2

Definition: the serum concentration of an antimicrobial achieved with optimal dosing

Answer 2

Breakpoint

Question 3

Def: The MIC inhibits the growth of the bacterium

Answer 3

Bacteriostatic

Question 4

Def. The MIC to inhibit and kill bacterium are close

Answer 4

Bacteriocidal

Question 5

What are the bacteriostatic drugs?

Answer 5

Lincosamides, macrolides, chloramphenicol, tetracyclines, sulfonamides, trimethoprim (BUT NOT TMS!). LMCTST (lewd mothers call teachers stupid taints).

Question 6

What are the concentration dependent drugs?

Answer 6

Flroroquinolones, aminoglycosies, metronidazole; azitrhomycin and tetracyclines have mixed

Question 7

What are the time dependent?

Answer 7

B-lactames, macrolides, lincosamides, tetracycline, chloramphenicol, potentiated sulfonamides

Question 8

What abx inhibit cell wall synthesis?

Answer 8

Beta lactams (penicillins, cephalosporins, penems), vancomycin

Question 9

Amoxicillin: Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 9

Spectrum - Excellent G+ (staph, strep, enterococci), some G-, Proteus, anaerobes. High conc - kidney, liver, lung. Meta: hydosis of the b-lactam ring. Renal tubule excretion

Question 10

Cephasporins: Spectrum? Distribution? Metabolism? Excretion?

Answer 10

Excellent against Gram +, proteus, klebsiella –> as generations advance get increase G- activity and less resistance. Distribution: blood, urine, bile, pleural, bone. Metabolism - cefotaxime deacetylaction. Excretion - renal

Question 11

Carbapenems: Spectrum? Excretion?

Answer 11

G+ and -, anaerobes; renal elimination

Question 12

Vancomycin: Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 12

Gram + only, tissues/fluids, no metabolism, renally excreted

Question 13

Protein synthesis inhibitors:

30S and 50s

Answer 13

30s - aminoglycosides and tetracycline

50s - chloramphenicl, macrolides and lincosamides

Question 14

Aminoglycosides: Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 14

Gram - infections, poor in CNS and respiratory tissue, no metabolism, renal excretion. 30s!

Question 15

Chloramphenicol: Where does it get high concenrtation? Metabolism? Excretion? Possible SE?

Answer 15

Distribution: CNS, eye, tissue. Metabolism - glucoronidations in the liver. Renal metobolite excretions. SE: Reversible BM suppression. 50s!

Question 16

MOA of Fusidic acid?

Answer 16

Inhibits protein synthesis

Question 17

Lincosamine: Spectrum? Where does it get high concenrtation? Metabolism?

Answer 17

Gram + mostly, distribution high in the liver, kidney, GI, brain, low in the CSF; metbolized in the liver. 50s!

Question 18

Macrolides: Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 18

Gram +, tissue concentration better than fluid - does not cross the BBB. Metabolized in the liver - cyp 450 enzyme inducers can result in treatment failure. Excreted in the bile and feces. 50s!

Question 19

Tetracyclines: Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 19

Broad (+/-, rickettsia). Penetrates brain, spinal fluid and prostate; renal and fecal excretion

Question 20

What drugs inhibit nucleic acid synthesis/function?

Answer 20

Nitrofurantion, nitroimidazoles, fluoroquinolones, rifampin

Question 21

Nitroimidazoles: Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 21

Anaerobic* and protozoal infections; high distribution in tissue; metabolism - liver oxidation and glucoronide formation. Eliminated in the urine. Metronidazole!

Question 22

FQs: MOA?Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 22

MOA - bind the DNA gyrase. Gram - and some gram +, distrubuted in fluids and tissue; Metabolism - enrofloxacin is de-ethulated to cipro. Excreted renal.

Question 23

Rifampin: MOA? SE?

Answer 23

Binds DNA-dependent RNA polymerase. Hepatotoxicity.

Question 24

What drug(s) cause damage to the cell membrane?

Answer 24

Polymixins and detergents

Question 25

What drugs work via metabolic antagonism?

Answer 25

Sulfonamines, Trimethoprime

Question 26

Sulfonamides: MOA?Spectrum? Where does it get high concenrtation? Metabolism? Excretion?

Answer 26

Inhibit folic acid synthesis; grame +/-, coccidian, chlamydia, toxo; Distributed in the tissues, CNS and synovial; Metabolized in the liver and lung*, excreted in the kidney

Question 27

Trimethoprim: MOA? Spectrum?

Answer 27

Inhibits dihydrofolate reductase that is needed for purine synthesis. Gram +

Question 28

What abx becomes formaldehyde in the urine?

Answer 28

Methenamine mandelate