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Key words: Buccal prochlorperazine - Oral prochlorperazine - Dizziness - Nausea - Vomiting
Summary
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.
Introduction
Dizziness results from many pathophysiological mechanisms and, therefore, to achieve effective treatment the precise cause of the dizziness must be identified at the outset. Vertigo, a relatively common complaintS associated with many causal factors4, is defined as an illusion of movement and is a subtype of dizziness often accompanied by nausea and/ or vomiting, indicative of a lesion somewhere in the vestibular system".
Prochlorperazine, a piperazine derivative of the phenothiazine family, is an effective antiemetic agent for chemotherapy and radiotherapy' and is frequently prescribed for the treatment of vertiginous disorders. However, the combination of reduced blood flow in the gastric mucosa, accelerated mucus production and a decreased parietal cell output resulting from vertigo"'2, together with a reduction in gastric emptying rate, tone and contraction displayed consistently in physically-induced vertigo3,7,10 may reduce the absorption of...