Antitubercular — First-Line TB (RIPE Regimen, 'P') Pregnancy: No sufficient clinical data in pregnant women; animal studies do not suggest detrimental effects. Use only when potential benefit clearly outweighs risk to the foetus. Contra-indicated in breast-feeding mothers.

Pyrazinamide

Brand names: Zinamide

Pyrazinamide is a first-line antituberculous drug used as part of combination therapy during the initial intensive phase of treatment for active tuberculosis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Under 50 kg: max 1.5 g/day (3 x 500 mg tablets); over 50 kg: max 2.0 g/day (4 x 500 mg tablets)

Route: Oral

Frequency: Once daily (standard unsupervised 2-month treatment)

Max: 2.0 g/day (over 50 kg); 1.5 g/day (under 50 kg)

Adults and adolescents. Used in combination with other anti-tubercular agents during the initial phase of treatment, over a total of 8 weeks (may be continued up to 3 months to prevent recurrent infection). Intermittent supervised 2-month therapy (only if daily administration not feasible): under 50 kg 2.0 g (4 tablets) three times a week; over 50 kg 2.5 g (5 tablets) three times a week. Must be administered under supervision of a physician trained in the management of tuberculosis. In meningeal or pericardial TB, a corticosteroid should be started at the same time.

Paediatric dose

Dose: 35 mg/kg

Route: Oral

Frequency: Once daily (standard unsupervised 2-month treatment)

Max: 1.5 g/day

Equivalent in children aged 4-10: 0.5-1 g (1-2 x 500 mg tablets); aged 11-14: 1-1.5 g (2-3 x 500 mg tablets). Intermittent supervised 2-month regimen (only if daily not feasible): 50 mg/kg three times weekly. Used in combination with other anti-tubercular agents. Verify against a children's formulary.

Dose adjustments

Renal

In renal impairment prescribe in emergencies only and administer intermittently; reduction in size and/or frequency of dose is recommended. Test liver and kidney function before and during treatment (every 3-4 weeks).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Severe hepatic impairment, acute liver disease (e.g. hepatitis) and up to 6 months after occurrence of hepatitis
Acute porphyria
Hyperuricaemia and/or acute gouty arthritis
Breast-feeding mothers

Side effects

Hepatic reaction (most common): raised serum transaminases, liver function disorders, hepatomegaly, jaundice, hepatic failure (which may be fatal)
Hyperuricaemia; gout, arthralgias
Gastrointestinal: loss of appetite, nausea, vomiting, heartburn, abdominal spasms, weight loss
Sideroblastic anaemia, thrombocytopenia (with or without purpura), porphyria, splenomegaly
Photosensitivity, flushing, rash, urticaria, pruritus, erythema multiforme

Clinical monograph

How it works

It is converted by mycobacterial pyrazinamidase to pyrazinoic acid, which is active against semi-dormant tubercle bacilli in the acidic environment of macrophages and inflammatory lesions, helping to shorten treatment duration.

Prescribing in practice

It is hepatotoxic, so baseline liver function should be assessed and the drug stopped if significant hepatitis develops; it is contraindicated in established severe liver disease.
It commonly raises serum urate and can precipitate gout or arthralgia.
It must always be given in combination with other antituberculous agents to prevent resistance, never as monotherapy.

Monitoring

Monitor liver function before and during treatment and review patients reporting joint symptoms or features of hepatitis.

Counselling the patient

Take all your tuberculosis tablets together exactly as prescribed and do not stop early.
Report nausea, vomiting, abdominal pain or yellowing of the skin or eyes promptly.
Joint aches can occur; mention them to your team rather than stopping treatment yourself.

Evidence & guidelines

Pyrazinamide is a core component of the standard four-drug initial-phase regimen recommended by NICE and WHO for active tuberculosis.

Reference: NICE NG33 (TB); WHO TB Treatment Guidelines 2022; PHE Tuberculosis Treatment Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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