Pyrazinamide


Concise Prescribing Info
Indications/Uses
TB.
Dosage/Direction for Use
Adult : PO As part of a mulitdrug regimen: <50 kg: 1.5 g daily or 2 g 3 times wkly; ≥50 kg: 2 g daily or 2.5 g 3 times wkly.
Dosage Details
Oral
Tuberculosis
Adult: As part of a mulitdrug regimen: For standard unsupervised 2-mth treatment: <50 kg: 1.5 g daily; ≥50 kg: 2 g daily. For intermittent supervised 2-mth treatment: <50 kg: 2 g 3 times wkly; ≥50 kg: 2.5 g 3 times wkly.
Child: As part of a mulitdrug regimen: For standard unsupervised 2-mth treatment: 35 mg/kg daily. For intermittent supervised 2-mth treatment: 50 mg/kg 3 times wkly.
Renal Impairment
May need dose reduction.
Hepatic Impairment
Severe: Contraindicated.
Administration
Should be taken with food.
Contraindications
Hypersensitivity. Hyperuricaemia and/or gouty arthritis, acute porphyria. Severe hepatic impairment.
Special Precautions
Patient w/ DM, history of gout. Mild to moderate hepatic and renal impairment. Pregnancy and lactation.
Adverse Reactions
Hyperuricaemia, leading to acute gout; anorexia, nausea, vomiting, aggravation of peptic ulcer, arthralgia, malaise, fever, sideroblastic anaemia, thrombocytopenia, dysuria. Rarely, photosensitivity, pellagra, rash.
Potentially Fatal: Hepatotoxicity.
MonitoringParameters
Monitor liver function, serum uric acid, sputum culture; chest x-ray 2-3 mth into treatment and at completion.
Overdosage
Symptoms: Liver toxicity and hyperuricaemia. Management: Empty the stomach by gastric lavage if necessary. Employ general supportive measures. May give benzodiazepine if there is evidence of CNS stimulation and probenecid for hyperuricaemia.
Drug Interactions
Antagonises the effect of uricosuric agents (e.g. probenecid, sulfinpyrazone). May reduce the contraceptive effect of oestrogens. May inactivate oral typhoid vaccine. May increase the serum concentration of ciclosporin. May enhance the hepatotoxic effect of rifampicin.
Lab Interference
May interfere w/ Acetest® and Ketostix® urine tests to produce pinkish-brown color.
Action
Description: Pyrazinamide may be bacteriostatic or bactericidal in action, depending on the concentration of the drug attained at the site of the infection and the susceptibility of the infecting organism. Its activity appears to partly depend on conversion of the drug to pyrazinoic acid (POA), which lowers the pH of the environment below that which is necessary for growth of Mycobacterium tuberculosis. Susceptible strains of M. tuberculosis produce pyrazinamidase, an enzyme that deaminates pyrazinamide to POA, and the in vitro susceptibility of a given strain of the organism appears to correspond to its pyrazinamidase activity.
Pharmacokinetics:
Absorption: Readily absorbed from the GI tract. Time to peak plasma concentration: Approx 2 hr.
Distribution: Widely distributed in body fluids and tissues, diffuses in the CSF and enters breast milk. Plasma protein binding: 50%.
Metabolism: Undergoes hepatic metabolism via hydrolysis to pyrazinoic acid (major active metabolite) and subsequently hydroxylated to 5-hydroxypyrazinoic acid (major excretory product).
Excretion: Via urine by glomerular filtration (approx 70% mainly as metabolites, approx 4% as unchanged drug). Half-life: Approx 9-10 hr.
Chemical Structure

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Storage
Store between 15-30°C.
MIMS Class
Disclaimer: This information is independently developed by MIMS based on Pyrazinamide from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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