Contraindications for Pilocarpine
Pilocarpine is absolutely contraindicated in patients with uncontrolled asthma, known hypersensitivity to pilocarpine, acute iritis, and narrow-angle (angle closure) glaucoma. 1
Absolute Contraindications
The FDA drug label explicitly lists the following absolute contraindications 1:
- Uncontrolled asthma - Pilocarpine increases airway resistance, bronchial smooth muscle tone, and bronchial secretions, which can precipitate bronchospasm 1
- Known hypersensitivity to pilocarpine 1
- Acute iritis - Miosis (pupillary constriction) is undesirable in this condition 1
- Narrow-angle (angle closure) glaucoma - Despite pilocarpine's use in treating some forms of glaucoma, it is contraindicated when miosis is undesirable 1
Critical Precautions Requiring Close Medical Supervision
Cardiovascular Disease
Patients with significant cardiovascular disease require cautious administration under close medical supervision because they may be unable to compensate for transient hemodynamic or rhythm changes induced by pilocarpine 1. The dose-related cardiovascular effects include hypotension, hypertension, bradycardia, and tachycardia 1. Pulmonary edema has been reported as a complication of pilocarpine toxicity from high ocular doses 1.
Respiratory Conditions
Pilocarpine should be administered with caution and under close medical supervision in patients with controlled asthma, chronic bronchitis, or chronic obstructive pulmonary disease requiring pharmacotherapy 1. The mechanism involves increased airway resistance and bronchial secretions 1.
Hepatobiliary Disease
Use caution in patients with known or suspected cholelithiasis or biliary tract disease because contractions of the gallbladder or biliary smooth muscle could precipitate cholecystitis, cholangitis, and biliary obstruction 1.
Renal Disease
Pilocarpine may increase ureteral smooth muscle tone and could theoretically precipitate renal colic or ureteral reflux, particularly in patients with nephrolithiasis 1.
Hepatic Impairment
Patients with moderate hepatic impairment (Child-Pugh score 7-9) should start at 5 mg twice daily rather than the standard dose, followed by adjustment based on response 1. Patients with mild hepatic insufficiency (Child-Pugh score 5-6) do not require dosage reductions 1. The use of pilocarpine in patients with severe hepatic impairment (Child-Pugh score 10-15) is not recommended 1.
Neuropsychiatric Considerations
Cholinergic agonists may have dose-related central nervous system effects, which should be considered when treating patients with underlying cognitive or psychiatric disturbances 1.
Important Drug Interactions
- Pilocarpine should be administered with caution to patients taking beta-adrenergic antagonists because of the possibility of conduction disturbances 1
- Concurrent use with other parasympathomimetic drugs would result in additive pharmacologic effects 1
- Pilocarpine might antagonize anticholinergic effects of drugs used concomitantly, which should be considered when anticholinergic properties contribute to therapeutic effect (e.g., atropine, inhaled ipratropium) 1
Common Pitfalls to Avoid
The most common adverse effect is excessive sweating, occurring in over 40% of patients, leading to discontinuation in approximately 2% of cases 2. Patients should be counseled that if they sweat excessively and cannot drink enough liquid, they should consult a physician immediately due to dehydration risk 1.
Visual disturbances, especially at night, may impair the ability to drive safely due to miosis and decreased depth perception 1. This is particularly important in patients with central lens changes 1.