pilokarpiin

Pilocarpine, known in Finnish as pilokarpiini, is a plant-derived alkaloid that acts as a direct-acting muscarinic (parasympathomimetic) agonist. It binds to muscarinic receptors and stimulates secretion and smooth muscle contraction, producing effects in the eye and various glands.

In the eye, pilocarpine causes contraction of the iris sphincter and the ciliary muscle, increasing aqueous humor drainage through the trabecular meshwork and lowering intraocular pressure. Systemically, it promotes secretions from salivary, sweat, and lacrimal glands.

Medicinal use: Ocular pilocarpine is used to treat glaucoma and to induce miosis during ophthalmic procedures. Eye drops are typically prepared in concentrations such as 0.5% to 2% and are applied several times daily. Systemic forms, including oral tablets or syrup, have been used to treat xerostomia (dry mouth) in Sjögren’s syndrome or after radiotherapy, but systemic use is less common due to widespread cholinergic side effects.

Adverse effects and safety: Ocular administration can cause local irritation, brow ache, and transient blurred vision. Systemic administration can produce sweating, excessive salivation, abdominal cramps, diarrhea, bronchospasm, and bradycardia. Caution is advised in patients with asthma or COPD, peptic ulcer disease, and in those with intestinal or urinary tract obstruction. It is contraindicated in individuals with hypersensitivity to pilocarpine.

History and notes: Pilocarpine is derived from Pilocarpus plants and has been used since the late 19th century as both a miotic agent and a secretagogue in various indications.