Comparison of buccal and oral prochlorperazine in the treatment of dizziness associated with nausea and/or vomiting.

The dizziness inherent in vertiginous disorders is often accompanied by nausea and/or vomiting. While prochlorperazine is effective in relieving nausea and vomiting, its low bioavailability following first pass metabolism in the liver and metabolism in the intestinal wall, compounded by the likelihood of regurgitation in the nauseous patient, may limit the therapeutic value of the oral preparation. A buccal preparation achieves higher plasma concentrations by direct absorption into the systemic circulation. In this randomised, double-blind, double-dummy trial in patients with vestibular disorders, in keeping with previous pharmacokinetic studies, buccal prochlorperazine achieved a significantly faster onset of effect compared with oral prochlorperazine (p = 0.04), and was significantly better in reducing the frequency of nausea (p = 0.02) and severity of vomiting (p = 0.05) at 24-36 hours. The frequency of vomiting was also reduced by buccal prochlorperazine compared with oral prochlorperazine, but this difference was only of borderline significance (p = 0.07). Buccal prochlorperazine was well tolerated and well rated by both patients and investigators, having no more adverse effects on the buccal mucosa than placebo and causing less drowsiness and sedation compared with the oral preparation. No advantages were reported for the oral preparation over buccal prochlorperazine. Buccal prochlorperazine is therefore safe and effective, and suitable for the treatment of dizziness associated with nausea and/or vomiting in patients suffering from vertiginous disorders.