Butorphanol.

Butorphanol (Stadol) is a synthetic agonist-antagonist analgesic from the 14-hydroxymorphinan series. Animal studies display analgesia, antitussive effects, low gastrointestinal activity, limited respiratory depression, some cardiovascular and skeletal muscle actions, diuresis, slight miosis and opiate antagonism. Butorphanol is metabolized in the liver with renal excretion, yielding a half-life of 3-4 h. Pain relief is good to excellent with parenteral administration in 90% of patients with moderate to severe pain. Surgical anesthetic indications involve preoperative and preinduction supplementation, balanced anesthesia and postoperative pain. Side effects are sedation, nausea, elevated pulmonary vascular pressures and rarely CNS excitation. Limited respiratory depression exists. Butorphanol is a potent analgesic agent with a favorable side effect profile.