Ethambutol is an antibiotic drug used to treat tuberculosis. It works by stopping the growth of tuberculosis bacteria. The drug is usually prescribed with other drugs used to treat tuberculosis such as rifampicin, pyrazinamide and isoniazid. Ethambutol is marketed under the product names Myambutol® and Servambutol®.

The medication comes in tablet form, and is typically prescribed to be taken once a day in the morning. Ethambutol should be taken with a full glass of water. The drug is also often taken with food, as it can cause an upset stomach.

It is important to be vigilant with antacid use while taking ethambutol, as most of these products contain aluminum which can inhibit absorption of the drug. If an antacid must be taken, doctors typically advise taking it some time before or after taking ethambutol — and at least an hour before and two hours after. It is also advisable to take an antacid without aluminum.

Patients taking ethambutol are usually monitored carefully in order to ensure that the drug is performing effectively and there are no adverse side effects. A doctor may perform regular liver, blood, and kidney tests. It is also common for a patient on the drug to have an eye exam about two to four times a year.

Doctors will typically get a full medical history from a patient before prescribing ethambutol. It is important for patients to disclose all medications, vitamins, and, particularly, antacids being taken as they can have a dramatic effect on the way the drug is absorbed and processed by the body. Previous conditions such as eye disease, kidney disease, and gout may make taking the drug too risky, though a doctor may find it acceptable to adjust the dosage or monitor the patient more carefully. Pregnant or nursing women should also report their condition to the prescribing doctor.

There are several reported side effects possible from taking ethambutol. The less-serious effects include vomiting, an upset stomach, low appetite, and numbness or a tingling sensation in the feet or hands. These problems should be reported to a doctor if they do not eventually disappear.

There are also several more severe side affects associated with Ethambutol which should receive immediate medical attention. The most distinctive of these is failure to see the colors green and red. There may also be abrupt changes in vision or blurred vision. Some patients can experience skin rash or itching.