Drug therapy reviews: evaluation of butorphanol tartrate.

The chemistry, pharmacology, uses, side effects, pharmacokinetics and dosage of butorphanol tartrate, a narcotic analgesic with antagonist properties, are reviewed. When administered intramuscularly or intravenously, butorphanol tartrate appears to be as effective for relieving moderate to severe pain as are pentazocine, meperidine and morphine. Butorphanol produces sedation more commonly and, at therapeutic dosages, depresses respiration as much as these other narcotic analgesics. A limited number of long-term clinical studies suggest a lower physical dependence liability with butorphanol than with other narcotic analgesics. Butorphanol is more expensive than morphine and, for most patients, offers no significant advantages over morphine for short-term use. Because butorphanol's cardiovascular effects are not completely understood, morphine also remains the drug of choice for pain associated with myocardial infarction.