Servambutol

Indications

Ethambutol is used to treat tuberculosis (TB), always together with other TB medicines such as Isoniazid, Rifampicin and Pyrazinamide, often as combined tablets. It is also used with other medicines for some infections caused by related bacteria (non-tuberculous mycobacteria), as decided by a specialist.

How It Works

Ethambutol stops TB bacteria from building their cell wall, so they cannot grow and multiply. Used with other TB medicines, it helps prevent the bacteria from becoming resistant.

Dosage and Administration

As prescribed by the doctor or the TB programme. The dose depends on body weight; for adults it is usually about 15 to 20 mg per kg once a day, often given as fixed-dose combination tablets in the first 2 months of treatment. Children's doses are also worked out by weight.

Take it once a day at the same time, with or without food. People with kidney problems may need a lower dose or fewer doses each week. Take every dose and finish the whole course, even after feeling better; stopping early can cause TB to return in a form that is harder to treat.

Interactions

Antacids containing aluminium can reduce absorption of Ethambutol; take them at least 4 hours apart. Tell your doctor about all medicines, vitamins and herbal products you take, as other TB medicines in the combination have many interactions of their own.

Contraindications

• Existing inflammation of the nerve of the eye (optic neuritis), unless the doctor decides it is essential
• Allergy to Ethambutol
• People who cannot notice or report changes in their eyesight (for example very young children), unless the doctor decides the benefit outweighs the risk

Side Effects

The most important side effect is damage to the nerve of the eye, which can cause blurred vision, reduced side vision or difficulty telling red from green. It is more likely at higher doses or with kidney problems, and usually improves if the medicine is stopped early.

Others: joint pain or gout (due to raised uric acid), nausea, stomach upset, loss of appetite, headache, dizziness, confusion, numbness or tingling in the hands and feet, and rash.

Get medical help at once for any change in your eyesight, including blurring or colours looking different; a severe skin rash, peeling or blistering; swelling of the face or difficulty breathing; or yellowing of the skin or eyes (which may come from the other TB medicines).

Pregnancy and Lactation

Ethambutol is considered safe in pregnancy and is part of standard TB treatment for pregnant women; untreated TB is a greater risk to mother and baby. It passes into breast milk in small amounts, and breastfeeding can usually continue.

Precautions and Warnings

• Have an eye test before starting if possible, and report any change in vision straight away; regular eye checks may be arranged during treatment.
• Take extra care with kidney disease, gout or existing eye problems.
• Kidney function and uric acid may be checked.

Overdose

Overdose can cause confusion, vision problems, stomach upset and fever. Contact a doctor or go to hospital straight away; treatment is supportive.

Therapeutic Class

Antituberculosis medicine (first-line).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.