Xerostomia: prevalence and pharmacotherapy. With special reference to beta-adrenoceptor antagonists

The main objective of this thesis was to estimate the prevalence of subjectively perceived dry mouth, xerostomia, in a representative general adult population, and the possible co-morbidity between xerostomia and on-going pharmacotherapy. Further, to evaluate the effects of beta-adrenoceptor antagonists on saliva flow rate and composition. The prevalence of xerostomia was evaluated by means of a questionnaire mailed to a random sample of 4.200 adult subjects living in the southern part of the province of Halland, Sweden. Three hundred men and equally many women aged 20, 30, 40, 50, 60, 70 and 80 years were selected from the national census register. From 3311 (81%) evaluable questionnaires was concluded that, in the studied population, 21.3% of the men and 27.3% of the women reported xerostomia. The difference between the sexes was statistically significant, women reporting higher prevalence of dry mouth than men. It was also found that xerostomia was significantly age-related. Further, it was demonstrated that there was a strong co-morbidity between reported prevalence of dry mouth and on-going pharmacotherapy. Generally, no specific drug or drug-group proved to be especially xerogenic, rather, polypharmacy was strongly correlated to reported symptoms of dry mouth, and it was also a significant correlation between increasing xerostomia and the number of medications taken. The effects of beta-adrenoceptor antagonists on saliva flow rate and composition were evaluated both in healthy volunteers and in hypertensive patients. The effects of one week of treatment with the non-selective (propranolol) and the beta 1-selective (atenolol) adrenoceptor antagonists were compared with that of placebo in three different clinical trials, including 38, 11 and 19 healthy volunteers, respectively. Two of these studies were focused on the effects on whole saliva secretion rate and composition and the third study on the secretions from the parotid and the submandibular-sublingual glands. Salivary composition but not saliva flow rates were affected by the beta-adrenoceptor antagonists, and the most pronounced effects were observed for total protein composition and amylase activity, both being significantly decreased during treatment with any of the antagonists, however, more accentuated during treatment with atenolol. Twelve hypertensive patients who were well-controlled in their blood-pressure by means of monotherapy with metoprolol, a beta 1-selective adrenoceptor antagonist, were observed during four weeks of withdrawal and after re-exposure to this antihypertensive treatment. The observed effects on salivary composition were essentially the same as those found in healthy volunteers. In the hypertensive group, however, whole saliva flow rates increased significantly on drug withdrawal and decreased again on re-exposure to metoprolol.