No

Antitubercular Agent

Treatment of tuberculosis and other mycobacterial diseases in conjunction with other antituberculosis agents

B

Hypersensitivity to ethambutol or any component; optic neuritis

Use only in children whose visual acuity can accurately be determined and monitored (not recommended for use in children <13 years of age unless the benefit outweighs the risk); dosage modification required in patients with renal insufficiency

1% to 10%:

Central nervous system: Headache, confusion, disorientation

Endocrine & metabolic: Acute gout or hyperuricemia

Gastrointestinal: Abdominal pain, anorexia, nausea, vomiting

<1%: Malaise, mental confusion, fever, rash, pruritus, abnormal LFTs, peripheral neuritis, optic neuritis, anaphylaxis

Symptoms of overdose include decrease in visual acuity, anorexia, joint pain, numbness of the extremities

Following GI decontamination, treatment is supportive

Decreased absorption with aluminum salts

Suppresses mycobacteria multiplication by interfering with RNA synthesis

Absorption: Oral: ~80%

Distribution: Well distributed throughout the body with high concentrations in kidneys, lungs, saliva, and red blood cells

Relative diffusion of antimicrobial agents from blood into CSF: Adequate with or without inflammation (exceeds usual MICs)

Ratio of CSF to blood level (%): Normal meninges: 0; Inflamed meninges: 25

Protein binding: 20% to 30%

Metabolism: 20% metabolized by the liver to inactive metabolite

Half-life: 2.5-3.6 hours

End-stage renal disease: 7-15 hours

Time to peak serum concentration: 2-4 hours

Elimination: ~50% excreted in the urine and 20% excreted in the feces as unchanged drug

Oral:

Note: A four-drug regimen (isoniazid, rifampin, pyrazinamide, and either streptomycin or ethambutol) is preferred for the initial, empiric treatment of TB. When the drug susceptibility results are available, the regimen should be altered as appropriate.

Children and Adults:

Daily therapy: 15-25 mg/kg/day (maximum: 2.5 g/day)

Directly observed therapy (DOT): Twice weekly: 50 mg/kg (maximum: 2.5 g)

DOT: 3 times/week: 25-30 mg/kg (maximum: 2.5 g)

Dosing interval in renal impairment:

Cl_cr 10-50 mL/minute: Administer every 24-36 hours

Cl_cr <10 mL/minute: Administer every 48 hours

Hemodialysis: Slightly dialyzable (5% to 20%); Administer dose postdialysis

Peritoneal dialysis: Dose for Cl_cr <10 mL/minute

Continuous arteriovenous or venovenous hemofiltration: Administer every 24-36 hours

May be administered with food as absorption is not affected, may cause gastric irritation

Periodic visual testing in patients receiving more than 15 mg/kg/day; periodic renal, hepatic, and hematopoietic tests

May cause confusion and disorientation

None reported

No information available to require special precautions

No effects or complications reported

Take as scheduled, with meals. Avoid missing doses and do not discontinue without consulting prescriber. You may experience GI distress (frequent small meals and good oral care may help), dizziness, disorientation, drowsiness (avoid driving or engaging in tasks that require alertness until response to drug is known). You will need to have frequent ophthalmic exams and periodic medical check-ups to evaluate drug effects. Report changes in vision, numbness or tingling of extremities, or persistent loss of appetite.

Reinforce compliance

Monitor visual testing periodically in patients receiving more than 15 mg/kg/day; periodic renal, hepatic, and hematopoietic tests

Tablet, as hydrochloride: 100 mg, 400 mg

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