Headache, dizziness, muscle pain, nausea, or diarrhea may occur. If you are being treated for "river blindness" (onchocerciasis), you may experience reactions to the dying parasites during the first 4 days of treatment, including joint pain, tender/swollen lymph nodes, eye swelling/redness/pain, weakness, vision changes, itching, rash, and fever. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To reduce dizziness upon standing, get up slowly when rising from a sitting or lying position.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: neck/back pain, swelling face/arms/hands/feet, chest pain, fast heartbeat, confusion, seizures, loss of consciousness.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.