Pilocarpine

Pilocarpine is a cholinergic alkaloid that is used as an ophthalmic miotic in the form of nitrate or hydrochloride salts.

• pilocarpine 1 - 4% is a direct cholinergic agonist which will cause miosis and accommodative spasm. It is used to reverse the action of mydriatics but its greatest therapeutic use is in lowering ocular pressure in both acute and chronic glaucoma by acting through the ciliary muscle to increase aqueous outflow

Advantages: proven efficacy and low cost.

Disadvantages: given 4 times daily resulting in reduced compliance in the long term.

Possible side effects include: miosis, accommodative spasm causing ocular pain. It should not be used to treat uveitic glaucoma. Pilocarpine may cause parasympathetic actions eg. salivation, sweating, hypertension, tachycardia, diarrhoea and vomiting, pulmonary oedema. Ciliary spasm may cause browache which may be more severe in the initial 2-4 weeks of treatment.

Since the introduction of beta-blockers, pilocarpine has become a second-line agent in the treatment of open angle glaucoma (1). However pilocarpine is now being relegated to a third-line agent with the availability of newer topical ocular hypotensives (1).

Notes:

• oral pilocarpine is used in the management of patients with xerostomia
• pilocarpine is a non-selective muscarinic agonist with a mild ß-adrenergic ability (2)
  • this parasympathomimetic agent enhances saliva secretion, ameliorating the sensation of dry mouth in patients with preserved exocrine tissue

Reference:

1. Prescriber 2001; 12 (5); 61-71.
2. Aframian DJ et al. Pilocarpine treatment in a mixed cohort of xerostomic patients Oral Diseases 2007;13 (1): 88–92