Oral pilocarpine HCl stimulates labial (minor) salivary gland flow in patients with Sjögren's syndrome.

Pilocarpine HCl has been shown to stimulate parotid and submandibular gland salivary flow. The purpose of this study was to determine whether this cholinergic-muscarinic drug also stimulates labial (minor) salivary gland (LSG) flow and to relate that with whole unstimulated salivary (WUS) flow rates. Subjects diagnosed with primary Sjögren's syndrome (SS-1; n = 9) or secondary Sjögren's syndrome (SS-2; n = 9) were enrolled in this study after meeting stringent enrollment criteria. An age-gender matched control group was also enrolled. The labial saliva was collected in a standardized manner on Periopaper for 5 min and the volume was analysed by the Periotron. Whole unstimulated salivary samples were collected for 5 min by the method of Mandel and Wotman (1976). Each subject was dosed with pilocarpine HCl (5 mg; tablets; p.o.). After 60 min the LSG flow as well as the WUS flow was determined again as previously. The results indicated a significant (> 180%) increase in both labial salivary gland flow as well as whole salivary flow in the SS-1 and SS-2 subjects (mean +/- s.e.m.): [SS-1: WUS = 0.1080 +/- 0.03 vs 0.2242 +/- 0.03 ml per 5 min; LSG = 93.1 +/- 22.2 vs 167.8 +/- 15.9 microliters/5 min; P < 0.001; SS-2: WUS = 0.1384 +/- 0.02 vs 0.2775 +/- 0.09 ml per 5 min; LSG = 97.7 +/- 20.2 vs 182.8 +/- 17.9 microliters per 5 min; P < 0.001]. These results indicate a significant increase in labial salivary gland flow as well as whole salivary flow as stimulated by pilocarpine HCl in Sjögren's syndrome patients.