Ethionamide
Mechanism :
Ethionamide is bacteriostatic or bactericidal, depending on the concentration of the drug and the susceptibility of the infecting organism. The exact mechanism of action of ethionamide has not been fully elucidated, but the drug appears to inhibit peptide synthesis in susceptible organisms.
Indication :
- M. tuberculosis resistant to isoniazid or rifampicin
Contraindications :
Contraindicated in patients with severe hepatic impairment and in patients who are hypersensitive to the drug.
Dosing :
15 to 20 mg/kg/day oral in 2 or 3 divided doses given after meals or 15 mg/kg/24 hours as a single daily dose. Max dose: 1000 mg/day.
Adverse Effect :
Psychotic disturbances (including mental depression), drowsiness, dizziness, headache, restlessness, postural hypotension, peripheral neuritis, diplopia, optic neuritis, blurred vision, pellagra-like syndrome, nausea, diarrhea, vomiting, excessive salivation, abdominal pain, metallic taste, stomatitis, anorexia, weight loss, hepatitis, hypersensitivity reactions (rash, photosensitivity, thrombocytopenia and purpura), hypoglycemia, gynecomastia, hypothyroidism, impotence and acne.
Interaction :
Temporarily raise serum concentrations of isoniazid. May potentiate the adverse effects of other antituberculous drugs administered concomitantly. In particular, convulsions have been reported when ethionamide is administered with cycloserine and special care should be taken when the treatment regimen includes both of these drugs. Excessive ethanol ingestion should be avoided because a psychotic reaction has been reported.
Hepatic Dose :
Mild to moderate hepatic impairment: Drug adjustment will be needed for pediatric population.
Severe hepatic impairment: Use is contraindicated.