Anti-TB drugs

Question 1

Rifampicin - MOA, side effects, cautions

Answer 1

MOA: DNA-dependent RNA polymerase inhibitor

Side effects:

• rash
• hepatitis
• DDI

Cautions: body fluid becomes red-orange
Resistance: rpoB

Question 2

Isoniazid - MOA, side effects, cautions

Answer 2

MOA: inhibit cell wall synthesis via inhibiting mycolic acid synthesis

Side effects:

• rash
• hepatitis
• peripheral neuropathy
• DDI: phenytoin

Cautions: hepatitis risk increases with age and alcohol; antimetabolite of pyroxidine –> vit B6 supplement to prevent neuropathy in pregnancy

Question 3

Pyrazinamide - MOA, side effects, cautions

Answer 3

MOA: unknown

Side effects

• hepatitis (MOST LIKELY)
• arthralgia
• gout

Caution: treat hyperUr only if patient has symptoms

Question 4

Ethambutol - MOA, side effects, cautions

Answer 4

MOA: inhibit cell wall synthesis via inhibition of arabinogalactan synthesis

Side effects:

• retrobulbar neuritis
• rash

Caution: may be unilateral, document visual acuity before treatment

Question 5

Streptomycin - MOA, side effects

Answer 5

MOA: irreversible inhibition of 30S

Side effects:

• ototoxicity
• nephrotoxicity

Question 6

Levofloxacin - MOA, side effects, use

Answer 6

MOA: inhibit DNA gyrase

Used as replacement drug for rifampicin or isoniazid in patients with MDR/XDR or deranged LFT

Question 7

Dapsone - MOA, side effects, use

Answer 7

MOA: anti-folate

Side effects
- methaemoglobinaemia

For treatment of leprosy with rifampicin and clofazimine

Question 8

Monitoring of therapy

Answer 8

LFT: HRZ
Serum urate: Z
Visual acuity: E
CBC/ D-dimer: thrombocytopenia/purpura by Rifampicin