Anti Tuberculosis Drugs

Question 1

Main prophylactic drug

Answer 1

Isoniazid (INH) or rifampin if intolerant.

Question 2

Mechanism of action of Isoniazid

Answer 2

Mycolid acid (cell wall) synthesis inhibitor

is a PRODRUG
resistance: mutation in katG gene that encodes CATALASE (converts the prodrug)

Question 3

Drugs most associated with Vitamin B6 deficiency

Why?

Answer 3

prescription drug is Isoniazid. Nonprescription is alcohol abuse. TB regiments last 6 to 10 months.

Drugs used for a long time will damage the liver. Liver will respond by producing more AST and ALT (aminotransferases). Vitamin B6 is the cofactor for these drugs thus will result in deficiency.

Question 4

Effects of vitamin B6 deficiency

Answer 4

Ammonia cannot be detoxified. Neuropathies. Sideroblastic Anemia. SLE in slow acetylators (rare)

Question 5

Rifampin mode of action

Answer 5

Blocks transcription by DNA dependent RNA polymerase

Question 6

Classic side effects of Rifampin

Answer 6

Red-orange metabolites (urine, tears)

Hepatic damage.

Question 7

First line supplemental drugs for TB

Answer 7

streptomycin
rifabutin
Quinolones (ciproflox, levoflox)

Question 8

Second Line drugs for TB

Answer 8

Amino Salicylic Acid (PAS)
cycloserine
Amikacin
Capreomycin
Ethionamide

Question 9

Indications for TB prophylaxis and the drug of choice

Answer 9

Household or close contact with active TB
+PPD in age under 35 or immunosuppressed

ISONIAZID (one drug only for prophylaxis)

Question 10

Primary drugs for TB

Answer 10

Isoniazid (INH)
rifampin
ethambutol
pyrazinamide