This medication may initially cause flushing, dizziness, weakness, nausea, drowsiness, stiffness, or feelings of tingling, heat, fatigue. If any of these effects continue or become bothersome, inform your doctor. In the unlikely event you have an allergic reaction to this drug, seek immediate medical attention. Symptoms of an allergic reaction include: rash, itching, swelling, dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.