Ethionamide
Indications
Ethionamide is used for:
Tuberculosis
Adult Dose
Oral
Tuberculosis, Active
15-20 mg/kg/day PO
Initiate dose at 250 mg/day for 1-2 days; THEN increase to 250 mg twice daily for 1-2 days with gradual increases to highest tolerated dose; 750 mg/day average dose
Not to exceed 1000 mg/day in 3-4 divided doses
Child Dose
Oral
Tuberculosis, Active
M. tuberculosis resistant to isoniazid or rifampin, or patient intolerant to drugs
10-20 mg/kg/day divided BID/TID PO OR
15 mg/kg PO qDay
No more than 1000 mg/day in 3-4 divided doses
Renal Dose
Renal Impairment
End-stage renal disease on hemodialysis: 250-500 mg/day
CrCl <30 mL/min: 250-500 mg/day
CrCl >30 mL/min: No dose adjustment necessary
Administration
Part of multi-drug regimen; not first-line treatment
Take with food
Contra Indications
Hypersensitivity to ethionamide. Severe hepatic impairment.
Precautions
Patient w/ depression or other psychiatric illness, DM, porphyria, thyroid dysfunction. Hepatic or renal impairment. Pregnancy and lactation. Monitoring Parameters Monitor serum ALT and AST at baseline and mthly; blood glucose and TSH periodically. Perform ophthalmologic exams prior to and during therapy. Evaluate CNS changes, ocular changes, and neuritis during therapy.
Pregnancy-Lactation
Pregnancy Category: C
Lactation: excretion in milk unknown; use with caution
Interactions
May potentiate AR of other anti-TB drugs. Additive CNS effect w/ isoniazid and cycloserine. May cause seizures w/ cycloserine.
Adverse Effects
Side effects of Ethionamide :
>10%
Disorder of gastrointestinal tract (50%)
Frequency Not Defined
Postural hypotension
Depression
Dizziness
Drowsiness
Headache
Peripheral neuropathy
Psychosis
Photosensitivity
Rash
Excessive salivation
Gynecomastia
Hypoglycemia
Impotence
Anorexia
Dyspepsia
Diarrhea
Nausea
Metallic taste
Vomiting
Thrombocytopenia
Elevated liver transaminases
Hepatitis
Optic neuritis
Visual changes
Mechanism of Action
Ethionamide's exact mechanism of action has not been fully elucidated, however, the drug appears to inhibit peptide synthesis. It may be bacteriostatic or bactericidal in action, depending on the concentration of drug attained at the site of infection and susceptibility of organism.