DRUG INTERACTIONS: This drug should not be used with the following medications because very serious interactions may occur: naltrexone. If you are currently using any of these medications, tell your doctor or pharmacist before starting this drug. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use, especially of: other medications for pain, cimetidine, isoniazid, MAO inhibitors (e.g., furazolidone, linezolid, moclobemide, phenelzine procarbazine, selegiline, isocarboxazid, tranylcypromine), anti-seizure drugs (e.g., carbamazepine, phenobarbital, phenytoin), anticholinergic drugs/antihistamines (e.g., hydroxyzine, oxybutynin, scopolamine), quinidine. Also report drugs that cause drowsiness such as: medicine for sleep (e.g., sedatives), tranquilizers, anti-anxiety drugs (e.g., diazepam), psychiatric medicines (e.g., phenothiazines such as chlorpromazine, or tricyclics such as amitriptyline), muscle relaxants, antihistamines that cause drowsiness (e.g., diphenhydramine). Acetaminophen is an ingredient in many nonprescription products and in some combination prescription medications. Read the labels carefully before taking other pain relievers, fever reducers, or cold products to see if they also contain acetaminophen. Consult your pharmacist if you are uncertain if your other prescription or nonprescription products contain acetaminophen. (Also see adult maximum daily dose information in Side Effects section). 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: persistent nausea or vomiting, stomach pain, slow breathing, slow heartbeat, cold/clammy skin, unusual sweating, loss of consciousness, yellowing eyes or skin, dark urine, extreme fatigue.