Antimycobacterial Drugs

Question 1

isoniazid: mechanism, uses, metabolism, side effects

Answer 1

• bactericidal
• inhibits synthesis of mycolic acid; prodrug that is activated by KatG protein and targets the InhA protein
• use: TB infection; for active TB always given in combination
• absorption/excretion: N-acetylated by N-acetyltransferase-2
• side effects: peripheral neuritis (improved with B6 administration), hepatotoxicity

Question 2

rifampin: use, mechanism, side effects

Answer 2

• treats TB
• inhibits RNA polymerase, thereby suppressing RNA synthesis
• bactericidal
• side effects: hepatotoxicity, potent inducer of multiple CYPs, orange color

Question 3

ethambutol: mechanism, side effects

Answer 3

• interferes with arabinosyl transferase, blocking cell wall synthesis
• tuberculostatic
• side effects: optic neuritis

Question 4

bactericidal drugs against TB

Answer 4

mnemonic: RIPS TB apart!!

isoniazid, rifampin, pyrazinamide, streptomycin

Question 5

pyrazinamide: use, mechanism, -static or -cidal, side effect

Answer 5

• treats TB, particularly useful for CNS involvement
• blocks mycolic acid synthesis by inhibiting fatty acid synthase I
• bactericidal
• side effect: hepatotoxicity

Question 6

streptomycin: mechanism, use, side effects

Answer 6

• binds to several ribosomal sites
• usually reserved for the most serious forms of TB because of its adverse effects
• side effects: ototoxicity, nephrotoxicity

Question 7

rifabutin

Answer 7

single-agent prophylaxis of MAC

Question 8

single-agent prophylaxis of MAC

Answer 8

rifabutin

Question 9

clarithromycin: use, -static or -cidal

Answer 9

• part of multi-drug regimen for treatment of MAC
• also prophylaxis
• bactericidal

Question 10

most common multi-drug therapy for MAC

Answer 10

rifabutin + clarithromycin

Question 11

drugs used in treatment of leprosy

Answer 11

dapsone, clofazimine, rifampin

Question 12

dapsone: uses, mechanism, side effects

Answer 12

• treatment of leprosy, prophylaxis and treatment of Pneumocystis jiroveci
• structural analog of PABA, inhibits synthesis of folic acid
• side effects: hemolytic anemia, methemoglobinemia

Question 13

clofazimine: use, mechanism

Answer 13

• treatment of leprosy

- binds to mycobacterial DNA, interfering with reproduction and growth

Question 14

bacteriostatic drug against TB

Answer 14

ethambutol

Question 15

particularly useful for CNS penetration in treatment of TB

Answer 15

pyrazinamide

Question 16

interferes with arabinosyl transferase

Answer 16

ethambutol

Question 17

blocks mycolic acid synthesis by inhibiting fatty acid synthase I

Answer 17

pyrazinamide

Question 18

anti-TB agent that binds to several ribosomal sites

Answer 18

streptomycin

Question 19

treatment of leprosy, prophylaxis and treatment of Pneumocystis jiroveci

Answer 19

dapsone

Question 20

structural analog of PABA, inhibits synthesis of folic acid

Answer 20

dapsone

Question 21

side effects: hemolytic anemia, methemoglobinemia

Answer 21

dapsone

Question 22

• treatment of leprosy

- binds to mycobacterial DNA, interfering with reproduction and growth

Answer 22

clofazimine

Question 23

side effects: peripheral neuritis (improved with B6 administration), hepatotoxicity

Answer 23

isoniazid

Question 24

side effects: hepatotoxicity, potent inducer of multiple CYPs, orange color

Answer 24

rifampin