Ethambutol (Myambutol)

Category:

Miscellaneous

Description:

Antituberculosis agent

Indications:

Adjunct in treatment of pulmonary tuberculosis
Mycobacterium avium complex (MAC) in AIDS (2^nd line) (non-FDA approved)

Contraindications:

Optic neuritis
Child <13 years

Precautions:

Pregnancy category B; compatible with breast feeding
Renal disease diabetic retinopathy
Cataracts, ocular defects, hepatic and hematopoietic disorders, gout

Adverse Reactions (Side Effects):

CNS: confusion, disorientation, dizziness, fever, hallucinations, headache, malaise
EENT: bloody sputum, blurred vision, changes in color perception, decreased visual acuity, optic neuritis, photophobia
GI: abdominal distress, anorexia, nausea, vomiting
HEME: thrombocytopenia
METAB: acute gout, elevated uric acid, liver function impairment
MS: joint pain
SKIN: dermatitis, pruritis

Dosage:

Administered orally

Adult and Child >13 years: Tuberculosis: Initial treatment: PO 15 mg/kg/day as a single daily dose; Retreatment: PO 25 mg/kg/day as a single dose for 2 months with at least 1 other drug, then decrease to 15 mg/kg/day as single daily dose.
Mycobacterium avium complex in AIDS: PO 15 mg/kg with 3 or 4 other antimycobacterial agents

Special considerations:

Initial therapy in tuberculosis should include 4 drugs; isoniazid, rifampin, pyrazinamide, and ethambutol, until drug susceptibility results available
Administer with meals to decrease GI symptoms

Source: Operational Medicine 2001, Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300