WARNING: THIS MEDICINE CONTAINS ACETAMINOPHEN. Severe and sometimes fatal liver problems, including the need for liver transplant, have been reported with the use of acetaminophen. Most cases of these liver problems occurred in patients taking excessive doses of acetaminophen (more than 4000 mg per day). Also, patients who developed these liver problems were often using more than 1 medicine that contained acetaminophen. Discuss any questions or concerns with your doctor. Some medicines or medical conditions may interact with this medicine. INFORM YOUR DOCTOR OR PHARMACIST of all prescription and over-the-counter medicine that you are taking. DO NOT TAKE THIS MEDICINE if you are taking sodium oxybate (GHB), or any other medicine containing tramadol or acetaminophen. ADDITIONAL MONITORING OF YOUR DOSE OR CONDITION may be needed if you are taking alpha-2 receptor blockers (eg, yohimbine), anorexiants (eg, phentermine), anticoagulants (eg, warfarin), azole antifungals (eg, ketoconazole), butyrophenones (eg, haloperidol), carbamazepine, cyclobenzaprine, digoxin, isoniazid, linezolid, lithium, loxapine, macrolide antibiotics (eg, erythromycin), certain medicines for mental or mood disorders (eg, olanzapine), molindone, nefazodone, opioid pain medicines (eg, codeine, hydrocodone), phenothiazines (eg, promethazine), quinidine, rifampin, serotonin-norepinephrine reuptake inhibitors (SNRIs) (eg, duloxetine), selective serotonin reuptake inhibitors (SSRIs) (eg, fluoxetine, paroxetine), sleeping medicines (eg, zolpidem), St. John's wort, thioxanthenes (eg, thiothixene), tiagabine, tricyclic antidepressants (eg, amitriptyline), or "triptans" (eg, sumatriptan). Tell your doctor if you are taking furazolidone or a monoamine oxidase inhibitor (MAOI) (eg, phenelzine, selegiline) or if you have taken one of these medicines within the last 14 days. DO NOT START OR STOP any medicine without doctor or pharmacist approval. Inform your doctor of any other medical conditions, including heart problems (eg, cor pulmonale), liver problems (eg, hepatitis), pancreas problems, kidney problems, thyroid problems, prostate problems (eg, enlargement of the prostate gland), a blockage in the bladder, diabetes, high blood pressure, metabolism problems, allergies, pregnancy, or breast-feeding. Tell your doctor if you have or recently have had any head injury, brain injury or tumor, increased pressure in the brain, or infection of the brain or nervous system. Tell your doctor if you have a history of lung or breathing problems (eg, asthma, chronic obstructive pulmonary disease / COPD); seizures (eg, epilepsy); recent stomach or bowel surgery, or any other stomach or bowel problem (eg, pain, inflammation, ulcers); mood or mental problems (eg, depression); or suicidal thoughts or actions. Tell your doctor if you drink alcohol or if you are going through withdrawal from alcohol or other substances. USE OF THIS MEDICINE IS NOT RECOMMENDED if you have severe or persistent diarrhea due to taking an antibiotic; liver problems; suicidal thoughts or actions; or a history of alcohol or other substance abuse or addiction. USE OF THIS MEDICINE IS NOT RECOMMENDED if you are intoxicated with alcohol or certain medicines, including opioids or narcotics (eg, morphine, codeine), or sedatives or sleeping medicines (eg, temazepam, zolpidem). Use of this medicine in CHILDREN is not recommended; safety and effectiveness in children have not been confirmed. Contact your doctor or pharmacist if you have any questions or concerns about using this medicine.