WARNING: This medicine is a narcotic pain reliever that may become habit-forming. Do NOT exceed the recommended dose, take for longer than prescribed, or take more often than prescribed without checking with your doctor. THIS MEDICINE MAY ALSO CAUSE SEVERE BREATHING PROBLEMS. This effect may be worse if you take it with alcohol, with other narcotic pain relievers, or with certain other medicines. Ask your doctor or pharmacist if you have questions about which medicines may add to this effect. Contact your doctor right away if you experience slow or shallow breathing. 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 also taking sodium oxybate (GHB). ADDITIONAL MONITORING OF YOUR DOSE OR CONDITION may be needed if you are taking anticholinergics (eg, oxybutynin, scopolamine), mixed agonist/antagonist pain medicines (eg, buprenorphine, butorphanol, pentazocine), naltrexone, other narcotic pain relievers (eg, codeine, morphine, oxycodone), phenothiazines (eg, chlorpromazine), or tricyclic antidepressants (eg, amitriptyline). Tell your doctor if you are taking a monoamine oxidase inhibitor (MAOI) (eg, phenelzine) or have taken one 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 severe drowsiness, a recent head injury, growths in the brain (eg, lesions, tumors), increased pressure in the head, liver or kidney problems, gallbladder problems, pancreas problems, stomach or bowel problems (eg, inflammation, pseudomembranous colitis), stomach pain, allergies, pregnancy, or breast-feeding. Tell your doctor if you have a history of heart problems (eg, cor pulmonale), low blood pressure, dehydration, low blood volume, chronic obstructive pulmonary disease (COPD) or other lung or breathing problems (eg, asthma, emphysema, bronchitis, sleep apnea), adrenal gland problems (eg, Addison disease), enlarged prostate, urinary blockage or trouble urinating, thyroid problems, seizures (eg, epilepsy), curvature of the spine, low blood oxygen levels (hypoxia), high blood carbon dioxide levels (hypercapnia), or recent stomach or bowel surgery. Tell your doctor if you have a personal or family history of mental or mood problems (eg, depression), alcohol or other substance abuse or dependence, or suicidal thoughts or attempts. Tell your doctor if you drink alcohol; have symptoms of alcohol withdrawal; are in poor health; will be having surgery; or are in shock caused by heart problems, blood vessel problems, or severe bleeding. USE OF THIS MEDICINE IS NOT RECOMMENDED if you are having an asthma attack. USE OF THIS MEDICINE IS NOT RECOMMENDED if you have difficult or slowed breathing, severe asthma, or known or suspected bowel blockage (paralytic ileus). Contact your doctor or pharmacist if you have any questions or concerns about taking this medicine.