DRUG INTERACTIONS: Inform your doctor of all the medicines you may use (both prescription and nonprescription), especially: cimetidine, erythromycin, troleandomycin, mexiletine, tacrine, barbiturates, disulfiram, rifampin, thiabendazole, birth control pills, rifabutin, ticlopidine, quinolone antibiotics, beta- blockers, phenytoin, halothane (an anesthetic), zileuton, allopurinol, lithium, carbamazepine, fluvoxamine (an SSRI antidepressant), St John's wort. Avoid drinking large amounts of beverages containing caffeine (e.g., coffee, tea, colas) or eating large amounts of chocolate. Caffeine can increase side effects of this medication. Smoking affects this medication. Be sure to tell your doctor if you smoke or use nicotine. Inform your doctor if you stop smoking. Your dose may need to be adjusted. Do not start or stop any medicine without doctor or pharmacist approval.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include fast or irregular heartbeat, nausea or vomiting, unusual nervousness or restlessness, agitation, irritability, headache, and seizures.

NOTES: Do not change your diet without first checking with your doctor. Large amounts of char-broiled foods or a high protein, low carbohydrate diet can affect the action of this medication. Do not change brands of this medication without consulting your doctor or pharmacist. Not all brands are identical in action.

MISSED DOSE: If you miss a dose, take it as soon as remembered; do not take if it is almost time for the next dose. Instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.

STORAGE: Store at room temperature away from moisture and sunlight. Do not store in the bathroom.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).