Adult: In combination with other antituberculosis agents: For standard unsupervised 2-month initial treatment phase: Patients weighing <50 kg: 1,500 mg once daily; ≥50 kg: 2,000 mg once daily. For intermittent supervised 2-month initial treatment phase: Patients weighing <50 kg: 2,000 mg 3 times a week; ≥50 kg: 2,500 mg 3 times a week. Alternative dosing recommendations: 15-30 mg/kg once daily (up to 3,000 mg daily) or 50-75 mg/kg twice weekly based on lean body weight. Dosage and treatment recommendations may vary among countries (refer to local guidelines). Child: In combination with other antituberculosis agents: For standard unsupervised 2-month initial treatment phase: 35 mg/kg once daily. For intermittent supervised 2-month initial treatment phase: 50 mg/kg 3 times a week. Alternative dosing recommendations: 15-30 mg/kg once daily (up to 3,000 mg daily) or 50-75 mg/kg twice weekly based on lean body weight. Dosage and treatment recommendations may vary among countries (refer to local guidelines).
What are the brands available for Pyrazinamide in Hong Kong?
Pyrafat
Pyrazinamide Atlantic
Renal Impairment
Dose reduction may be required.
Hepatic Impairment
Severe: Contraindicated.
Administration
Pyrazinamide May be taken with or without food.
Contraindications
Hypersensitivity. Hyperuricaemia and/or acute gout. Severe hepatic impairment.
Special Precautions
Patient with history of gout; diabetes mellitus; history of alcoholism; porphyria. Renal impairment. Children. Pregnancy and lactation. Concomitant use with hepatotoxic agents (particularly rifampicin).
Adverse Reactions
Significant: Dose-related hepatotoxicity (e.g. transient ALT or AST elevations, jaundice, hepatitis, liver atrophy); hyperuricaemia. Blood and lymphatic system disorders: Rarely, sideroblastic anaemia with erythroid hyperplasia, thrombocytopenia, vacuolation of erythrocytes. Gastrointestinal disorders: Nausea, vomiting, aggravation of peptic ulcer. General disorders and administration site conditions: Fever, malaise. Immune system disorders: Hypersensitivity reactions (e.g. urticaria, pruritus). Investigations: Rarely, increased serum iron concentration. Metabolism and nutrition disorders: Anorexia, porphyria. Musculoskeletal and connective tissue disorders: Mild arthralgia, myalgia. Renal and urinary disorders: Dysuria. Skin and subcutaneous tissue disorders: Rash, photosensitivity, acne, flushing.
Perform culture and susceptibility tests; consult local institutional recommendations before treatment initiation due to antibiotic resistance risks. Perform liver function test before therapy, then every 2-4 weeks or periodically as necessary during therapy. Evaluate renal function before treatment. Obtain serum uric acid levels at baseline and periodically during treatment. Perform chest x-ray 2-3 months into therapy and upon completion. Monitor pyrazinamide serum concentrations when clinically indicated.
Overdosage
Symptoms: Liver toxicity and hyperuricaemia.
Management: Supportive and symptomatic treatment. Perform gastric lavage or induce emesis. Closely monitor liver function and employ a high-carbohydrate, low-fat diet. May give benzodiazepine or short-acting barbiturates in case of CNS stimulation and probenecid for hyperuricaemia.
Drug Interactions
May antagonise the effect of uricosuric drugs (e.g. probenecid). May reduce the therapeutic effect of oral typhoid vaccine. Increased risk of hepatotoxicity with rifampicin.
Lab Interference
Interferes with Acetest® and Ketostix® urine tests, producing a pinkish-brown colour.
Action
Description: Overview: Pyrazinamide is a niacinamide derivative antituberculosis agent. It may be bactericidal or bacteriostatic against Mycobacterium tuberculosis, depending on the drug concentration attained at the infection site. Mechanism of Action: The exact mechanism of action of pyrazinamide has not been fully elucidated. Susceptible strains of M. tuberculosis produce pyrazinamidase, which converts pyrazinamide to the active metabolite pyrazinoic acid (POA). It has been shown that POA reduces the pH of the environment below the level that promotes the growth of M. tuberculosis; this action appears to contribute to the antimycobacterial activity of pyrazinamide. Pharmacodynamics: The exact mechanism of resistance to pyrazinamide has not been determined; however, certain pyrazinamide-resistant M. tuberculosis strains do not appear to produce pyrazinamidase and are therefore unable to convert pyrazinamide to POA. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Time to peak plasma concentration: Approx 2 hours. Distribution: Widely distributed into body tissues and fluids, including liver and lung; also diffuses into the CSF. Enters breast milk (small amounts). Plasma protein binding: 50%. Metabolism: Primarily metabolised in the liver via hydrolysis into pyrazinoic acid (major active metabolite), which is then hydroxylated to 5-hydroxypyrazinoic acid (major excretory product). Excretion: Via urine (approx 70%; mainly as metabolites, approx 4% as unchanged drug). Elimination half-life: 9-10 hours.
Chemical Structure
Pyrazinamide Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 1046, Pyrazinamide. https://pubchem.ncbi.nlm.nih.gov/compound/Pyrazinamide. Accessed Feb. 24, 2026.
J04AK01 - pyrazinamide ; Belongs to the class of other drugs used in the systemic treatment of tuberculosis.
References
AFT Pharmaceuticals Ltd. PDP-Pyrazinamide 500 mg Tablets data sheet 06 September 2018. Medsafe. http://www.medsafe.govt.nz. Accessed 09/12/2025.AFT-Pyrazinamide Tablet 500 mg (Y.S.P. Industries [M] Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 09/12/2025.Brayfield A, Cadart C (eds). Pyrazinamide. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/12/2025.Joint Formulary Committee. Pyrazinamide. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 09/12/2025.Pyrazinamide 500 mg Tablets (Macleods Pharma UK Limited). MHRA. https://products.mhra.gov.uk. Accessed 13/02/2025.Pyrazinamide Tablet (Hikma Pharmaceuticals USA Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 09/12/2025.Pyrazinamide, PZA. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed 13/02/2025.Pyrazinamide. UpToDate Lexidrug, AHFS DI (Adult and Pediatric) Online. American Society of Health-System Pharmacists, Inc. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 09/12/2025.Pyrazinamide. UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 09/12/2025.Zinamide Tablets 500 mg (Genus Pharmaceuticals Limited T/A Genus Pharmaceuticals). MHRA. https://products.mhra.gov.uk. Accessed 09/12/2025.
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