Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Ethambutol can cause serious vision problems, including vision loss that may be permanent. Stop using ethambutol and call your doctor at once if you have any problems with one or both of your eyes, such as:
blurred vision or trouble focusing;
loss of vision in one eye that lasts an hour or longer;
increased sensitivity of your eyes to light;
loss of color vision; or
pain with eye movement, pain behind your eyes.
Call your doctor at once if you have:
new or worsening cough with fever, trouble breathing;
numbness of tingling in your hands or feet;
confusion, hallucinations;
fever, swollen glands, painful mouth sores, skin sores, cold or flu symptoms, general ill feeling;
easy bruising or bleeding (nosebleeds, bleeding gums);
chest pain or shortness of breath with mild exertion;
little or no urinating;
liver problems--upper stomach pain, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Common side effects may include:
itching or rash;
joint pain;
headache, dizziness; or
nausea, vomiting, stomach pain, indigestion, loss of appetite.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Ethambutol side effects (more detail)
