Effects of droperidol in management of vestibular disorders.

The chemo-therapy of vestibular disease has involved a wide spectrum of pharmacological agents insofar as their mode of action is concerned. In our experience, however, droperidol is one pharmaceutical agent which is remarkably effective in depressing vestibular disturbance regardless of etiology. This medication (also called Inapsine‡) belongs to a relatively new class of compounds known as butyrophenones and its pharmacological action can best be described as a dopa blocking agent. The activity of droperidol on the nervous system first became evident when it was used in combination with the potent analgesic fentanyl citrate in order to produce an anesthetic condition that has been termed neuroleptanalgesia. This mixture (also called Innovar‡) is rapid in action and results in complete suppression of vestibular activity of both normal subjects and those with Meniere's disease as described by Dowdy, et al., in a preliminary report. These impressive results have prompted us to evaluate the effectiveness of this medication in the treatment of different disorders of the labyrinth. The patients chosen for evaluation were referred for vestibular examination at the Toronto General and St. Michael's Hospitals. Electronystagmography was used to record objectively the effects of the drugs being tested while subjective symptoms including side effects were also noted. These studies involved 20 patients receiving Innovar while 12 patients were tested with Inapsine. Innovar administered in a single dose (droperidol 5 mg, fentanyl 0.1 mg) to patients undergoing acute episodes of vestibular disease (vestibular neuronitis and Meniere's disease) was found effective in the following symptoms and/or signs: nausea, vertigo, nystagmus, the positive past-pointing test and the Romberg test. Innovar appeared to be effective in the amelioration of vomiting although the population was too small to demonstrate statistical significance in this regard. The drug mixture appeared to have no effect on improving auditory acuity and had no significant effects on tinnitus. Adverse reactions to the drug combination were unusual, and, occurring in three patients, were mild as manifested by drowsiness. Since the above findings confirmed the marked effectiveness of the fentanyl-droperidol mixture in the management of vestibular disease, it was decided to determine the relative effectiveness of the droperidol component alone and this was determined by comparing the effectiveness of the drug with placebo in a double-blind study. Review of our findings involving this double-blind study indicates significant responses to Inapsine. This therapy clearly provided the statistically significant response (P <.01, Fisher's Exact Test). This was particularly apparent at the 60-minute evaluation point. While some of the patients receiving Inapsine had recovered earlier, by 60 minutes none of the placebo patients but all of the Inapsine patients had recovered from the vestibular symptoms of Meniere's disease. Some adverse side effects consisting of drowsiness and slight drop in blood pressure occurred in some patients; these can be minimized by a decreased dose (2.5 mg).