Pyrazinamide

Description

DESCRIPTION: Pyrazinamide, USP the pyrazine analogue of nicotinamide, is an antituberculous agent. It is a white crystalline powder, stable at room temperature, and sparingly soluble in water. Pyrazinamide USP has the following structural formula: Each pyrazinamide tablet, USP for oral administration contains 500 mg of pyrazinamide and the following inactive ingredients: corn starch, colloidal silicon dioxide, magnesium stearate, povidone, sodium starch glycolate and talc. pyrazinamide-structure

What Is Pyrazinamide Used For?

INDICATIONS & USAGE: Pyrazinamide is indicated for the initial treatment of active tuberculosis in adults and children when combined with other antituberculous agents. (The current recommendation of the CDC for drug- susceptible disease is to use a six-month regimen for initial treatment of active tuberculosis, consisting of isoniazid, rifampin and pyrazinamide given for 2 months, followed by isoniazid and rifampin for 4 months.* 4 ) (Patients with drug-resistant disease should be treated with regimens individualized to their situation. Pyrazinamide frequently will be an important component of such therapy.) (In patients with concomitant HIV infection, the physician should be aware of current recommendation of CDC. It is possible these patients may require a longer course of treatment). It is also indicated after treatment failure with other primary drugs in any form of active tuberculosis. Pyrazinamide should only be used in conjunction with other effective antituberculous agents. *See recommendations of Center for Disease Control (CDC) and American Thoracic Society for complete regimen and dosage recommendations. 4

Dosage and Administration

DOSAGE & ADMINISTRATION: Pyrazinamide should always be administered with other effective antituberculous drugs. It is administered for the initial 2 months of a 6-month or longer treatment regimen for drug-susceptible patients. Patients who are known or suspected to have drug-resistant disease should be treated with regimens individualized to their situation. Pyrazinamide frequently will be an important component of such therapy. Patients with concomitant HIV infection may require longer courses of therapy. Physicians treating such patients should be alert to any revised recommendations from CDC for this group of patients. Usual dose: Pyrazinamide is administered orally, 15 to 30 mg/kg once daily. Older regimens employed 3 or 4 divided doses daily, but most current recommendations are for once a day. Three grams per day should not be exceeded. The CDC recommendations do not exceed 2 g per day when given as a daily regimen (see table). Alternatively, a twice weekly dosing regimen (50 to 75 mg/kg twice weekly based on lean body weight) has been developed to promote patient compliance with a regimen on an outpatient basis. In studies evaluating the twice weekly regimen, doses of pyrazinamide in excess of 3 g twice weekly have been administered. This exceeds the recommended maximum 3 g/daily dose. However, an increased incidence of adverse reactions has not been reported. This table is taken from the CDC-American Thoracic Society joint recommendations. 4 Recommended Drugs for the Initial Treatment of Tuberculosis in Children and Adults Daily Dose * Maximal Daily Dose in Children and Adults Twice Weekly Dose Drug Children Adults Children Adults Isoniazid 10 to 20 mg/kg PO or IM 5 mg/kg PO or IM 300 mg 20 to 40 mg/kg Max. 900 mg 15 mg/kg Max. 900 mg Rifampin 10 to 20 mg/kg PO 10 mg/kg PO 600 mg 10 to 20 mg/kg Max. 600 mg 10 mg/kg Max. 600 mg Pyrazinamide 15 to 30 mg/kg PO 15 to 30 mg/kg PO 2 g 50 to 70 mg/kg 50 to 70 mg/kg Streptomycin 20 to 40 mg/kg IM 15 mg/kg** IM 1 g** 25 to 30 mg/kg IM 25 to 30 mg/kg IM Ethambutol 15 to 25 mg/kg PO 15 to 25 mg/kg PO 2.5 g 50 mg/kg 50 mg/kg Definition of abbreviations: PO = perorally; IM = intramuscularly. * Doses based on weight should be adjusted as weight changes. **In persons older than 60 yrs of age the daily dose of streptomycin should be limited to 10 mg/kg with a maximal dose of 750 mg.

Side Effects (Adverse Reactions)

ADVERSE REACTIONS: General: Fever, porphyria and dysuria have rarely been reported. Gout (see PRECAUTIONS: ). Gastrointestinal: The principal adverse effect is a hepatic reaction (see WARNINGS:). Hepatotoxicity appears to be dose related, and may appear at any time during therapy. GI disturbances including nausea, vomiting and anorexia have also been reported. Hematologic and Lymphatic: Thrombocytopenia and sideroblastic anemia with erythroid hyperplasia, vacuolation of erythrocytes and increased serum iron concentration have occurred rarely with this drug. Adverse effects on blood clotting mechanisms have also been rarely reported. Other: Mild arthralgia and myalgia have been reported frequently. Hypersensitivity reactions including rashes, urticaria, and pruritis have been reported. Fever, acne, photosensitivity, porphyria, dysuria and interstitial nephritis have been reported rarely.

Contraindications

CONTRAINDICATIONS: Pyrazinamide is contraindicated in persons:

Pregnancy and Breastfeeding

Pregnancy: Teratogenic Effects Animal reproduction studies have not been conducted with pyrazinamide. It is also not known whether pyrazinamide can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Pyrazinamide should be given to a pregnant woman only if clearly needed.

Nursing Mothers: Pyrazinamide has been found in small amounts in breast milk. Therefore, it is advised that pyrazinamide be used with caution in nursing mothers taking into account the risk-benefit of this therapy. 9

Overdosage

OVERDOSAGE: Overdosage experience is limited. In one case report of overdose, abnormal liver function tests developed. These spontaneously reverted to normal when the drug was stopped. Clinical monitoring and supportive therapy should be employed. Pyrazinamide is dialyzable. 13

How Supplied

HOW SUPPLIED Pyrazinamide Tablets, USP 500 mg are round, white to off white uncoated, scored tablets with notches, debossed "F" above the score and "43" below the score and plain on other side. Tablets are supplied in the following strengths and package configurations: Package configuration NDC number Bottles of 10 33342-447-03 Bottles of 30 33342-447-07 Bottles of 60 33342-447-09 Bottles of 90 33342-447-10 Bottles of 100 33342-447-11 Bottles of 500 33342-447-15 Carton of 100 Tablets (10 x 10 unit dose) 33342-447-12 Store at 20° to 25° C (68° F to 77° F); excursions permitted between 15° to 30° C (59° F to 86° F) [see USP Controlled Room Temperature]. Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. Manufactured for: Macleods Pharma USA, Inc. Princeton, NJ 08540 Manufactured by: Macleods Pharmaceutical Ltd. Daman, (U.T.), INDIA Revised: December 2022