May cause CNS depression. May cause hypotension (use with caution in hypovolemia, cardiovascular disease or drugs which may exaggerate hypotensive effects). May obscure diagnosis or clinical course of acute abdominal conditions. Use with caution in adrenal insufficiency (including Addison’s disease), biliary tract dysfunction (acute pancreatitis may cause constriction of sphincter of Oddi), decreased hepatic function, morbidly obese patients, prostatic hyperplasia and/or urinary stricture, decreased renal function. Use with caution in history of drug abuse or acute alcoholism (potential for drug dependency exists). Use with extreme caution in head injury, intracranial lesions, or elevated intracranial pressure (exaggerated elevation of intracranial pressure may occur). Use with caution 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 thyroid dysfunction, and in debilitated patients (greater potential for critical respiratory depression). Concurrent use of agonist/antagonist analgesics may precipitate withdrawal symptoms and/or reduced analgesic efficacy in patients following prolonged therapy with μ-opioid agonists. Abrupt discontinuation following prolonged use may also lead to withdrawal symptoms.