May cause CNS depression. May cause hypotension (use with caution in hypovolemia, cardiovascular disease (including acute MI), or drugs which may exaggerate hypotensive effects (including phenothiazines or general anesthetics). May obscure diagnosis or clinical course of acute abdominal conditions. Use with caution in adrenal insufficiency (including Addison’s disease), in biliary tract dysfunction (acute pancreatitis may cause constriction of sphincter of Oddi), and in CNS depression or coma. Potential for drug dependency. Tolerance, psychological and physical dependence may occur with prolonged use. Use with extreme caution in head injury, intracranial lesions, or elevated intracranial pressure. Use with caution in hepatic dysfunction, in morbidly obese patients, in prostatic hyperplasia and/or urinary stricture, in renal dysfunction, and in pre-existing respiratory compromise (hypoxia and/or hypercapnia), COPD or other obstructive pulmonary disease, and kyphoscoliosis or other skeletal disorder which may alter respiratory function (critical respiratory depression may occur). Use with caution in history of seizure disorders, and in thyroid dysfunction. Effects may be potentiated when used with other sedative drugs or ethanol. Some preparations contain sulfites (may cause allergic reactions). Use with caution in debilitated patients (greater potential for critical respiratory depression), and in the elderly. Infants under 3 months of age more susceptible to respiratory depression. Concurrent use of agonist/antagonist analgesics may precipitate withdrawal symptoms and/or reduced analgesic efficacy following prolonged therapy with μ-opioid agonists. Abrupt discontinuation following prolonged use may also lead to withdrawal symptoms.