Activates opiate receptor in limbic system of CNS, analgesic similar to morphine on a milligram for milligram basis, agonist and antagonist properties; may be preferred for chest pain in setting of acute MI as it reduces the myocardial oxygen demand without reducing the blood pressure.
Chest pain associated with acute MI; moderate to severe acute pain; pulmonary edema, with or without associated chest pain (morphine remains first line).
Head injury or undiagnosed abdominal pain, diarrhea caused by poisoning, hypovolemia, hypotension.
10 mg in 1-mL ampule (10 mg/mL), 20 mg in 1-mL ampule.
Dosage and Administration
Adult: 2-5 mg slowly IV; may repeat 2-mg doses PRN to maximum dose of 10 mg.
Pediactric: Not recommended
Duration of Action
Onset: 2-3 minutes.
Peak Effect: variable.
Duration: 3-6 hours.
Pregnancy safety: Category B. Use with caution in patients with impaired respiratory function. May precipitate withdrawal syndromes in narcotic-dependant patients. Naloxone should be readily available.