Antimycobacterial drugs Flashcards Preview

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Flashcards in Antimycobacterial drugs Deck (11):
1

prophylaxis for TB

isoniazid.

2

tx for TB

rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE for treatment)

3

MAC prophylaxis

azithromycin, rifabutin.

4

MAC treatment

more drug resistant than TB. try azithromycin or clarithromycin + ethambutol. can add rifabutin or ciprofoxacin

5

M. leprae tx

dapsone and rifampin for tuberculoid form. add clofazimine for lepramatous.

6

isoniazid MOA

decreases the synthesis of mycolic acids. Note that it must be metabolized to its active metabolite by bacterial catalase peroxidase

7

isoniazid use and considerations

MTB. only agent used as solo prophylaxis against TB. different INH half-lives exist based on fast vs. slow acetylators.

8

isoniazid toxicities

INH injures neurons and hepatocytes. see neurotoxicity and hepatotoxicity. giving pyridoxine (vit B6) can prevent neurotoxicity and lupus.

9

rifamycin MOA and cosiderations

4 Rs of rifampin:
1. Inhibits DNA-dependent RNA polymerase
2. ramps up microsomal cytochrome P-450
3. red/orange urine and sweat
4. rapid resistance if used alone
5. rifampin ramps up the P-450 more than rifabutine, so use rifabutin in pts with HIV.
this drug is used for MTB primarily. it also delays resistance to dapsone when used for leprosy. use for prophylaxis in ppl exposed to HiB

10

pyrazinamide

used for TB. uncertain mechanism (may acidify intracellular environment). effective in the acidic pH of phagolysosomes. toxicities include hyperuricemia and hepatotoxicity

11

ethambutol: MOA, toxicity,

decr. carb polymerization of mycobacterium cell wall by blocking arabinosyltransferase. used against tb. causes optic neuropathy