Pyrazinamide (Pyrazinamide)
Also sold as: Pyzina, Pyrazinamide BP, Rifater
Pregnancy
Cat C
Lactation
Caution
Schedule
H1
Forms
Tablet 500mg +2
Indications
- Active tuberculosis — intensive phase only (first 2 months of DOTS regimen)
- MDR-TB (as part of specialist-designed regimen)
- TB meningitis (extended use sometimes recommended)
Adult Dosing
Tuberculosis — intensive phase
Weight-based: <50 kg: 1.5 g OD; 50–74 kg: 2 g OD; ≥75 kg: 2.5 g OD (max 2.5 g/day)
Once daily for 2 months (intensive phase only)
Used only in intensive phase; sterilizes persisting bacilli in acidic environment of TB granulomas; take with or without food
Tuberculosis — standard weight-based dosing
25 mg/kg OD (max 2 g)
Daily for 2 months
Standard guideline dose; weight-based preferred for accuracy
Pediatric Dosing
Higher mg/kg than adults; rounded to nearest convenient tablet dose; part of paediatric DOTS regimen for 2 months
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| CrCl ≥30 mL/min | Standard dose |
| CrCl 10–30 mL/min | Reduce dose or extend interval to every 48 hours; monitor uric acid and LFTs |
| CrCl <10 mL/min or haemodialysis | Avoid if possible; if essential use 25 mg/kg thrice weekly after dialysis |
Hepatic Adjustment
Contraindicated in severe hepatic impairment — pyrazinamide is the most hepatotoxic of the first-line anti-TB drugs. Avoid in acute hepatic failure. Use with extreme caution in pre-existing liver disease; monitor LFTs very closely.
Pregnancy & Lactation
Pregnancy: Category C
Limited safety data. WHO 2022 guidelines recommend including pyrazinamide in the intensive phase of TB treatment in pregnancy. Risk of untreated TB is greater than drug risk. Monitor LFTs closely.
Lactation: Caution
Excreted in breast milk. WHO supports breastfeeding during TB treatment. Monitor infant for jaundice or GI symptoms.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| Allopurinol | Pyrazinamide inhibits renal uric acid excretion — raises uric acid levels, reducing allopurinol's uricosuric efficacy; if gout develops, allopurinol may be ineffective while on PZA | Moderate |
| Rifampicin | Additive hepatotoxicity — used together in DOTS regimen; monitor LFTs monthly; highest hepatotoxicity risk is in first 2 months (intensive phase) when both are used simultaneously | Moderate |
| Probenecid | Pyrazinamide antagonizes the uricosuric effect of probenecid — reduces its efficacy for gout treatment | Minor |
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Side Effects
Common
- Hyperuricaemia (inhibits tubular secretion of uric acid) — may be asymptomatic
- Arthralgias and myalgias (non-gouty, often polyarticular — manage with NSAIDs if needed)
- Nausea, vomiting, anorexia
- Photosensitivity (use sunscreen)
- Flushing
Serious / Discontinue If
- Hepatotoxicity — most hepatotoxic of first-line anti-TB agents; ranges from asymptomatic enzyme elevation to fulminant hepatic failure
- Acute gouty arthritis (in predisposed patients — elevated uric acid precipitates gout)
- Sideroblastic anaemia (rare)
- Thrombocytopenia (rare)
Contraindications
- Severe hepatic impairment or acute hepatic failure
- Acute gout attack (relative — discuss with specialist)
- Hypersensitivity to pyrazinamide
- Severe renal impairment (CrCl <10 mL/min) — use with extreme caution only
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Pyzina 500mg | Macleods | ₹22/10 tab |
| Pyrazinamide BP 500mg | Various | ₹18/10 tab |
Monitoring Required
- Baseline LFTs before starting — pyrazinamide is the most hepatotoxic first-line drug
- Monthly LFTs during intensive phase (2 months)
- Serum uric acid at baseline and monthly — act if >9 mg/dL or if symptomatic gout develops
- Joint examination — assess for gouty arthritis vs drug-related arthralgia
- Stop immediately if ALT >3× ULN with symptoms or >5× ULN asymptomatic
Patient Counseling Points
- This medicine is used only for the first 2 months of TB treatment — do not take it beyond the prescribed period
- You may notice joint pains (especially in the knees, ankles, fingers) — this is a known side effect; paracetamol or ibuprofen can help; report severe joint pain
- Avoid prolonged sun exposure — use sunscreen and cover up outdoors (photosensitivity)
- Report immediately: yellowing of eyes or skin, severe stomach pain, nausea/vomiting — signs of liver damage
- If you have a history of gout, inform your doctor before starting this medicine
- Take with or without food; if stomach upset occurs, take with a light meal
- Do not self-stop — completing the intensive phase is critical for TB cure
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Clinically reviewed by: Dr. Anand Kumar, MD (Pulmonology), Chest Physician, TB & Chest Hospital, New Delhi
Last reviewed: 2026-04-30
References
- WHO Treatment of Drug-Susceptible Tuberculosis Guidelines, 2022
- RNTCP DOTS Guidelines, Central TB Division, MoHFW India
- ATS/CDC/IDSA Statement: Treatment of Tuberculosis, 2003 (updated 2016)
- Micromedex Drug Interactions — Pyrazinamide, 2024
- BNF (British National Formulary) — Pyrazinamide monograph, 2024