[Oral premedication with clonidine as an alternative in dental practice. The effects on the pain threshold, blood pressure and salivary flow].

BACKGROUND: Clonidine, an alpha 2-adrenoceptor agonist, has been recently shown to be effective in conscious sedation because of its analgesic and sedative properties, having also proven to be active in reducing neuroendocrine responses to stressful stimuli perioperatively. The current study was designed to investigate the efficacy of 150 micrograms oral clonidine as a premedicant in dentistry. METHODS: In a prospective, randomized, double-blind controlled clinical trial, 40 patients, aged 16-64 yr, undergoing conservative, or prosthetic, or dental surgery procedures, received placebo (n = 20) or 150 micrograms of oral clonidine (n = 20) 90 min before the estimated time of induction of local anesthesia. A blinded observer recorded: salivary flow, systolic and diastolic blood pressure each 30 min lasting 2-3 hours, as well as the degree of pain and sedation intra and postoperatively. RESULTS: Clonidine produced significant salivary flow reduction (p < 0.001) and sedation (p < 0.001) as well as significant difference in postoperative pain scores (p < 0.05) compared to placebo. Xerostomia persisted postoperatively in clonidine premedicated patients as compared to those given the placebo (p < 0.01). Systolic blood pressure decreased significantly only after 120 (p < 0.01) and 150 min (p < 0.001) following clonidine pretreatment, but none of the patients were treated for hypotension. 55% of the clonidine treated patients positively evaluated the experience. CONCLUSIONS: These results suggest that a dose of 150 micrograms of clonidine, given orally 90 min preoperatively, is an effective premedication in dentistry, without causing excessive haemodynamic depression and sedation, and moreover confirm that the oral route of administration is very well accepted.