<p>This medication is generally well tolerated. However, high doses may cause headache, nausea or irritability. If any of these effects continue or become bothersome, inform your doctor. Notify your doctor if you develop: muscle weakness, slow reflexes, confusion, swelling of the feet or ankles, black tar-like stools, coffee-ground vomit. If you notice other effects not listed above, contact your doctor or pharmacist.</p>