Anti-TB Drugs

Question 1

Active TB - initial TX

Answer 1

2 months long
4 drugs until susceptibility established
Isoniazid/Rifampin/Pyrazinamide + Ethambutol

Question 2

Active TB - continuation TX

Answer 2

4-7 months
Isoniazid/Rifampin
Directly Observed Therapy

Question 3

Latent Infection TX recommended for…

Answer 3

high risk of developing active disease:

HIV+, immunosuppressants, small children, DM, CRF

Question 4

Latent infection drugs

Answer 4

Isoniazid daily OR twice weekly direct observation for 6-9 months

Question 5

Isoniazid MOA

Answer 5

Bactericidal for rapidly dividing organisms, interferes with cell wall formation.
Bactericidal

Question 6

Isoniazid kinetics

Answer 6

absorbed well PO
distributes well, including living cells - important for penetration into caseating lesions
Decrease dose in hepatic failure

Question 7

Isoniazid ADR

Answer 7

Neuritis possible

Hepatotoxicity possible

Question 8

Rifampin MOA

Answer 8

binds to DNA-dependant RNA polymerase…. inihbit RNA synthesis
Bactericidal, synergistic with INH

Question 9

Rifampin Kinetics

Answer 9

well absorbed PO
excreted mainly into bile
can enhance metabolism of drugs via p450 induction

Question 10

Rifampin ADR

Answer 10

potentially hepatotoxic

Question 11

Rifampin uses outside TB

Answer 11

Very effective against H. flu, N. meningitidis, pseudomonas, chlamydia
we try to reserve it for TB