Pilocarpine

INDICATIONS AND USAGE: Pilocarpine hydrochloride tablets, USP are indicated for 1) the treatment of symptoms of dry mouth from salivary gland hypofunction caused by radiotherapy for cancer of the head and neck; and 2) the treatment of symptoms of dry mouth in patients with Sjogren's syndrome.

CLINICAL PHARMACOLOGY: 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 pilocarpine hydrochloride 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 pilocarpine hydrochloride 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 pilocarpine hydrochloride tablets to stimulate saliva production was assessed. In these trials using varying doses of pilocarpine hydrochloride 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 pilocarpine hydrochloride tablets and was maintained throughout the duration (12 weeks) of t

DOSAGE AND ADMINISTRATION: Regardless of the indication, the starting dose in patients with moderate hepatic impairment should be 5 mg twice daily, followed by adjustment based on therapeutic response and tolerability. Patients with mild hepatic insufficiency do not require dosage reductions. The use of pilocarpine in patients with severe hepatic insufficiency is not recommended. If needed, refer to the Hepatic Insufficiency subsection of the Precautions section of this label for definitions of mild, moderate and severe hepatic impairment. Head & Neck Cancer Patients: The recommended initial dose of pilocarpine hydrochloride tablets is 5 mg taken three times a day. Dosage should be titrated according to therapeutic response and tolerability. The usual dosage range is 15-30 mg per day. (Not to exceed 10 mg per dose.) Although early improvement may be realized, at least 12 weeks of uninterrupted therapy with pilocarpine hydrochloride tablets may be necessary to assess whether a beneficial response will be achieved. The incidence of the most common adverse events increases with dose. The lowest dose that is tolerated and effective should be used for maintenance. Sjogren's Syndrome Patients: The recommended dose of pilocarpine hydrochloride tablets is one tablet (5 mg) taken four times a day. Efficacy was established by 6 weeks of use.

ADVERSE REACTIONS: Head & Neck Cancer Patients: In controlled studies, 217 patients received pilocarpine, of whom 68% were men and 32% were women. Race distribution was 91% Caucasian, 8% Black, and 1% of other origin. Mean age was approximately 58 years. The majority of patients were between 50 and 64 years (51%), 33% were 65 years and older and 16% were younger than 50 years of age. The most frequent adverse experiences associated with pilocarpine hydrochloride tablets were a consequence of the expected pharmacologic effects of pilocarpine. Adverse Event Pilocarpine HCl Placebo 10 mg t.i.d. (30 mg/day) 5 mg t.i.d. (15 mg/day) (t.i.d.) n=121 n=141 n=152 Sweating 68% 29% 9% Nausea 15 6 4 Rhinitis 14 5 7 Diarrhea 7 4 5 Chills 15 3 <1 Flushing 13 8 3 Urinary Frequency 12 9 7 Dizziness 12 5 4 Asthenia 12 6 3 In addition, the following adverse events (≥3% incidence) were reported at dosages of 15-30 mg/day in the controlled clinical trials: Adverse Event Pilocarpine HCl Placebo 5-10 mg t.i.d. (15-30 mg/day) (t.i.d.) n=212 n=152 Headache 11% 8% Dyspepsia 7 5 Lacrimation 6 8 Edema 5 4 Abdominal Pain 4 4 Amblyopia 4 2 Vomiting 4 1 Pharyngitis 3 8 Hypertension 3 1 The following events were reported with treated head and neck cancer patients at incidences of 1% to 2% at dosages of 7.5 to 30 mg/day: abnormal vision, conjunctivitis, dysphagia, epistaxis, myalgias, pruritus, rash, sinusitis, tachycardia, taste perversion, tremor, voice alteration. The following events were reported rarely in treated head and neck cancer patients (<1%): Causal relation is unknown. Body as a whole: body odor, hypothermia, mucous membrane abnormality Cardiovascular: bradycardia, ECG abnormality, palpitations, syncope Digestive: anorexia, increased appetite, esophagitis, gastrointestinal disorder, tongue disorder Hematologic: leukopenia, lymphadenopathy Nervous: anxiety, confusion, depression, abnormal dreams, hyperkinesia, hypesthesia, nervousness, paresthesias, speech disorder, twitching Respiratory: increased sputum, stridor, yawning Skin: seborrhea Special senses: deafness, eye pain, glaucoma Urogenital: dysuria, metrorrhagia, urinary impairment In long-term treatment were two patients with underlying cardiovascular disease of whom one experienced a myocardial infarct and another episode of syncope. The association with drug is uncertain. Sjogren's Syndrome Patients: In controlled studies, 376 patients received pilocarpine, of whom 5% were men and 95% were women. Race distribution was 84% Caucasian, 9% Oriental, 3% Black, and 4% of other origin. Mean age was 55 years. The majority of patients were between 40 and 69 years (70%), 16% were 70 years and older and 14% were younger than 40 years of age. Of these patients, 161/629 (89/376 receiving pilocarpine) were over the age of 65 years. The adverse events reported by those over 65 years and those 65 years and younger were comparable except for notable trends for urinary frequency, diarrhea, and dizziness. The incidences of urinary frequency and diarrhea in the elderly were about double those in the non-elderly. The incidence of dizziness was about three times as high in the elderly as in the non-elderly. These adverse experiences were not considered to be serious. In the 2 placebo-controlled studies, the most common adverse events related to drug use were sweating, urinary frequency, chills, and vasodilatation (flushing). The most commonly reported reason for patient discontinuation of treatment was sweating. Expected pharmacologic effects of pilocarpine include the following adverse experiences associated with pilocarpine hydrochloride tablets: Adverse Event Pilocarpine HCl Placebo 5 mg q.i.d. (20 mg/day) (q.i.d.) n=255 n=253 Sweating 40% 7% Urinary Frequency 10 4 Nausea 9 9 Flushing 9 2 Rhinitis 7 8 Diarrhea 6 7 Chills 4 2 Increased Salivation 3 0 Asthenia 2 2 In addition, the following adverse events (≥3% incidence) were reported at dosages of 15-30 mg/day in the controlled clinical trials: Adverse Event

WARNINGS: Cardiovascular Disease: Patients with significant cardiovascular disease may be unable to compensate for transient changes in hemodynamics or rhythm induced by pilocarpine. Pulmonary edema has been reported as a complication of pilocarpine toxicity from high ocular doses given for acute angle-closure glaucoma. Pilocarpine should be administered with caution in and under close medical supervision of patients with significant cardiovascular disease. Ocular: Ocular formulations of pilocarpine have been reported to cause visual blurring which may result in decreased visual acuity, especially at night and in patients with central lens changes, and to cause impairment of depth perception. Caution should be advised while driving at night or performing hazardous activities in reduced lighting. Pulmonary Disease: Pilocarpine has been reported to increase airway resistance, bronchial smooth muscle tone, and bronchial secretions. Pilocarpine hydrochloride should be administered with caution to and under close medical supervision in patients with controlled asthma, chronic bronchitis, or chronic obstructive pulmonary disease requiring pharmacotherapy.

CONTRAINDICATIONS: Pilocarpine hydrochloride tablets are contraindicated in patients with uncontrolled asthma, known hypersensitivity to pilocarpine, and when miosis is undesirable, e.g., in acute iritis and in narrow-angle (angle closure) glaucoma.

MANAGEMENT OF OVERDOSE: Fatal overdosage with pilocarpine has been reported in the scientific literature at doses presumed to be greater than 100 mg in two hospitalized patients. 100 mg of pilocarpine is considered potentially fatal. Overdosage should be treated with atropine titration (0.5 mg to 1.0 mg given subcutaneously or intravenously) and supportive measures to maintain respiration and circulation. Epinephrine (0.3 mg to 1.0 mg, subcutaneously or intramuscularly) may also be of value in the presence of severe cardiovascular depression or bronchoconstriction. It is not known if pilocarpine is dialyzable.