Pharmacodynamics

Pilocarpine is a cholinergic parasympathomimetic agent exerting a broad spectrum of pharmacologic effects with predominant muscarinic action. Pilocarpine, in appropriate dosage, can increase secretion by the exocrine glands. The sweat, salivary, lacrimal, gastric, pancreatic, and intestinal glands and the mucous cells of the respiratory tract may be stimulated. When applied topically to the eye as a single dose it causes miosis, spasm of accommodation, and may cause a transitory rise in intraocular pressure followed by a more persistent fall. Dose-related smooth muscle stimulation of the intestinal tract may cause increased tone, increased motility, spasm, and tenesmus. Bronchial smooth muscle tone may increase. The tone and motility of urinary tract, gallbladder, and biliary duct smooth muscle may be enhanced. Pilocarpine may have paradoxical effects on the cardiovascular system. The expected effect of a muscarinic agonist is vasodepression, but administration of pilocarpine may produce hypertension after a brief episode of hypotension. Bradycardia and tachycardia have both been reported with use of pilocarpine.

In a study of 12 healthy male volunteers there was a dose-related increase in unstimulated salivary flow following single 5 and 10 mg oral doses of SALAGEN® Tablets. This effect of pilocarpine on salivary flow was time-related with an onset at 20 minutes and a peak effect at 1 hour with a duration of 3 to 5 hours (See Pharmacokinetics section).

Head & Neck Cancer Patients: In a 12 week randomized, double-blind, placebo-controlled study in 207 patients (placebo, N=65; 5 mg, N=73; 10 mg, N=69), increases from baseline (means 0. 072 and 0. 112 mL/min, ranges -0. 690 to 0. 728 and -0.380 to 1. 689) of whole saliva flow for the 5 mg (63%) and 10 mg (90%) tablet, respectively, were seen 1 hour after the first dose of SALAGEN® Tablets. Increases in unstimulated parotid flow were seen following the first dose (means 0. 025 and 0. 046 mL/min, ranges 0 to 0. 414 and -0. 070 to 1. 002 mL/min for the 5 and 10 mg dose, respectively). In this study, no correlation existed between the amount of increase in salivary flow and the degree of symptomatic relief.

Sjogren's Syndrome Patients: In two 12 week randomized, double-blind, placebo-controlled studies in 629 patients (placebo, N=253; 2. 5 mg, N=121; 5 mg, N=255; 5-7. 5 mg, N=114), the ability of SALAGEN® Tablets to stimulate saliva production was assessed. In these trials using varying doses of SALAGEN® Tablets (2.5-7.5 mg), the rate of saliva production was plotted against time. An Area Under the Curve (AUC) representing the total amount of saliva produced during the observation interval was calculated. Relative to placebo, an increase in the amount of saliva being produced was observed following the first dose of SALAGEN® Tablets and was maintained throughout the duration (12 weeks) of the trials in an approximate dose response fashion (See Clinical Studies section).

Pharmacokinetics

In a multiple-dose pharmacokinetic study in male volunteers following 2 days of 5 or 10 mg of oral pilocarpine hydrochloride tablets given at 8 a. m. , noontime, and 6 p. m. , the mean elimination half-life was 0. 76 hours for the 5 mg dose and 1. 35 hours for the 10 mg dose. Tmax values were 1. 25 hours and 0. 85 hours. Cmax values were 15 ng/mL and 41 ng/mL. The AUC trapezoidal values were 33 h(ng/mL) and 108 h(ng/mL), respectively, for the 5 and 10 mg doses following the last 6 hour dose.

Pharmacokinetics in elderly male volunteers (N=11) were comparable to those in younger men. In five healthy elderly female volunteers, the mean Cmax and AUC were approximately twice that of elderly males and young normal male volunteers.

Bookmark this page: