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.