Overview
DESCRIPTION Pyrazinamide, 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 has the following structural formula: Each pyrazinamide tablet for oral administration contains 500 mg of pyrazinamide and the following inactive ingredients: Corn Starch, Magnesium Stearate,...
Mechanism of Action
CLINICAL PHARMACOLOGY Pyrazinamide is well absorbed from the GI tract and attains peak plasma concentrations within 2 hours. Plasma concentrations generally range from 30 to 50 mcg/mL with doses of 20 to 25 mg/kg. It is widely distributed in body tissues and fluids including the liver, lungs and cerebrospinal fluid (CSF). The CSF concentration is approximately equal to concurrent steady-state plasma concentrations in patients with inflamed meninges. 1 Pyrazinamide is approximately 10% bound to plasma proteins. 2 The half-life (t 1/2 ) of pyrazinamide is 9 to 10 hours in patients with normal renal and hepatic function. The plasma half-life may be prolonged in patients with impaired renal or hepatic function.
Indications
- 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.
Common Doses
- 30 mg
- 2 g
- 70 mg
- 3 g
Dosage
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.
Contraindications
- CONTRAINDICATIONS Pyrazinamide is contraindicated in persons: with severe hepatic damage. who have shown hypersensitivity to it. with acute gout.
Side Effects
- 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.
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.