Ethambutol (E)

Update: January 2022

Forms and strengths

• 100 mg and 400 mg tablets
• 100 mg dispersible tablet, to be dispersed in 10 ml water

Dosage

• Child and adult: 15 to 25 mg/kg once daily
• Maximum dose: 1200 mg daily
• Renal insufficiency: 15 to 25 mg/kg 3 times a week

Contra-indications, adverse effects, precautions

• Do not administer to patients with severe renal impairment or optic neuritis (e.g. diabetic retinopathy).
• May cause:
  • dose-related retrobulbar optic neuritis, exarcerbated in renal impairment;
  • hypersensitivity reactions.
• The dosage must be carefully adjusted to the weight, especially for children under 5 years, as it is more difficult to detect visual changes at this age.
• For the management of adverse effects, see Appendix 17.
• Pregnancy: no contra-indication
• Breastfeeding: no contra-indication

Monitoring

• Symptomatic monitoring. 

Patient instructions

• Take with or without food.
• 100 mg dispersible tablets should be dispersed in 10 ml water.

Remarks

• For adults on drug-susceptible TB treatment, ethambutol is given as part of a fixed-dose combination.
• Ethambutol is also used in the treatment of drug-resistant TB treatment for longer duration. For treatment > 2 months, daily doses should be closer to 15 mg/kg and visual acuity and colour discrimination should be monitored.

Storage