You may notice that your sweat, urine, or saliva appears dark in color, such as red, brown, or black. This is not a harmful side effect, but it may cause staining of your clothes or bed sheets.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
- restless muscle movements in your eyes, tongue, jaw, or neck;
- worsening of tremors (uncontrolled shaking);
- high fever, stiff muscles, sweating, fast or uneven heartbeats, rapid breathing, feeling like you might pass out;
- seizure (convulsions);
- painful or difficult urination;
- severe nausea, vomiting, or diarrhea;
- uneven heart rate or fluttering in your chest;
- confusion, hallucinations, anxiety, agitation, depressed mood, thoughts of suicide or hurting yourself;
- chest pain or heavy feeling, pain spreading to the arm or shoulder.
Less serious side effects may include:
- mild nausea, dry mouth, loss of appetite, heartburn, diarrhea, constipation;
- headache, dizziness, drowsiness, blurred vision;
- sneezing, stuffy nose, cough, or other cold symptoms;
- sleep problems (insomnia), strange dreams;
- muscle pain, numbness or tingly feeling; or
- skin rash or itching.
This is not a complete list of side effects and others may occur.