SIDE EFFECTS: Nausea, vomiting, insomnia, constipation, dizziness and drowsiness may occur. If these effects continue or worsen, inform your doctor. Unlikely but report: blurred vision, unsteadiness, nausea, mood changes, confusion, slurred speech, rash, fever, headache, sore throat, unusual bleeding or bruising. Very unlikely but report: stomach pain, uncoordinated movements, yellowing of the eyes or skin, trouble breathing, swollen glands, unusual fatigue. May cause enlargement of the gums. This can be minimized by maintaining good oral hygiene with regular brushing, flossing and massaging of the gums. If you notice other effects not listed above, contact your doctor or pharmacist.

PRECAUTIONS: Tell your doctor if you have: blood disorders (e.g., porphyria), allergies (especially drug allergies), liver disease. Use caution operating machinery or performing tasks requiring alertness. Limit alcohol use as it may increase the drowsiness effect of this medication. Limit your caffeine usage. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is unknown if this drug is excreted into human breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Inform your doctor about all the medicine you use (both prescription and nonprescription) especially of blood thinners (warfarin), cimetidine, omeprazole, sucralfate, disulfiram, oral antifungal medication (azoles), xanthine drugs used for asthma (theophylline), isoniazid, folic acid, pyrimethamine, sulfa antibiotics, rifampin, trimethoprim, amiodarone, fluoxetine, anticancer drugs, valproic acid or divalproex, estrogens, disopyramide, levodopa, felodipine, primidone, felbamate, digoxin, narcotic pain medications (e.g., codeine). This drug may interfere with the effectiveness of birth control pills. Discuss using other methods of birth control with your doctor. Do not start or stop any medicine without doctor or pharmacist approval.

Report Problems to the Food and Drug Administration You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088. Need help identifying pills and medications? Use the pill identifier tool on RxList.