Anti TB Drugs

Question 1

What are the examples of Rifamycin?

Answer 1

Rifampicin (PO/IV); rifabutin (PO); rifapentine (PO)

Question 2

What are the adverse effects of Rifamycin?

Answer 2

• Orange-red discoloration of body fluids
• Enzyme induction P450 -caution with use of OCP, warfarin, antiepileptics, steroids, antifungals, protease inhibitors
• Hepatotoxicity
• Thrombocytopenia

Question 3

What is the mechanism of drug resistance of Rifamycin?

Answer 3

Resistance arises from mutations inrpoBgene (used in rapid diagnostics of drug resistant TB)

Question 4

What is the monitoring required for Rifamyacin?

Answer 4

• Check for drug interactions with concomitant medications
• Baseline LFT and at follow-up
• Advise patient to look for jaundice, RUQ tenderness, vomiting.
• Inform patient urine and body fluids will be red-orange color

Question 5

What is the mechanism of action of Rifamycin?

Answer 5

Inhibit bacterial DNA-dependent RNA polymerase

Question 6

What is the mechanism of action of isoniazid?

Answer 6

Inhibition of mycolic acid biosynthesis

Question 7

What are the adverse effects of isoniazid?

Answer 7

• Hepatotoxicity
• Peripheral neuropathy, ataxia, paresthesia -give with concomitant pyridoxine (Vitamin B6)
• Arthralgia
• Hypersensitivity
• Drug induced lupus like syndrome

Question 8

What is the monitoring required for isoniazid?

Answer 8

• Baseline LFT and at follow-up

- Give vitamin B6

Question 9

What are the adverse effects of pyrazinamide?

Answer 9

Baseline LFT and follow-up

Question 10

What is the mechanism of action of ethambutol?

Answer 10

Inhibition of mycobacterial cell wall formation

Question 11

what is the adverse effects of ethambutol?

Answer 11

Optic neuropathy

Question 12

what is the monitoring required for ethambutol

Answer 12

• Baseline Snellen visual acuity and Ishihara test

- Enquire regarding changes in red color discrimination and visual acuity