ISOPTO CARPINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ISOPTO CARPINE (ISOPTO CARPINE).
Pilocarpine, a direct-acting cholinergic agonist, stimulates muscarinic receptors (M3 subtype) in the ciliary muscle and iris sphincter muscle, causing miosis and contraction of the ciliary muscle. This opens the trabecular meshwork and increases aqueous humor outflow facility, reducing intraocular pressure in glaucoma. Also induces accommodation spasm.
| Metabolism | Primarily metabolized by plasma esterases via hydrolysis, with some hepatic metabolism. Half-life ~1-2 hours. Excreted renally as metabolites and unchanged drug. |
| Excretion | Primarily renal excretion of unchanged drug and metabolites; approximately 80% of a dose is eliminated via urine within 24 hours, with about 20% as unchanged pilocarpine. Biliary/fecal elimination accounts for less than 5%. |
| Half-life | Terminal elimination half-life is approximately 1.4 hours in healthy adults; clinically, this short half-life necessitates frequent dosing for sustained ocular effect. |
| Protein binding | Approximately 30% bound to plasma proteins, mainly albumin. |
| Volume of Distribution | Approximately 0.5 L/kg, indicating distribution largely into extracellular fluid; clinically, not extensively distributed to tissues. |
| Bioavailability | Ocular (topical): bioavailability is low due to nasolacrimal drainage and systemic absorption; exact % not well defined but systemic exposure is minimal with recommended ophthalmic dosing. |
| Onset of Action | Ocular (topical): miosis begins within 10-30 minutes; peak intraocular pressure reduction occurs at 2-4 hours. |
| Duration of Action | Ocular (topical): miosis lasts 4-8 hours; intraocular pressure reduction persists for 4-8 hours, requiring dosing every 6-8 hours for glaucoma. |
1 to 2 drops of a 1% to 4% solution in the affected eye(s) up to 4 times daily, as needed to reduce intraocular pressure.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment required for renal impairment; drug is minimally systemically absorbed and renally eliminated. |
| Liver impairment | No dosage adjustment required for hepatic impairment; drug is minimally systemically absorbed and primarily metabolized locally. |
| Pediatric use | Not recommended for use in children due to lack of safety and efficacy data; use only if potential benefit outweighs risk. |
| Geriatric use | Use with caution in elderly patients due to increased risk of systemic anticholinergic effects (e.g., bradycardia, bronchospasm); consider lower concentration or frequency. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ISOPTO CARPINE (ISOPTO CARPINE).
| Breastfeeding | Limited data; no M/P ratio available. Pilocarpine may suppress lactation via cholinergic effect. Use caution; monitor infant for cholinergic side effects. |
| Teratogenic Risk | Insufficient human data. Animal studies: no teratogenicity at ocular doses. Risk cannot be excluded. Avoid in first trimester unless benefit outweighs risk. |
| Fetal Monitoring | Monitor intraocular pressure, visual fields, and optic nerve status. In pregnancy, monitor fetal growth and amniotic fluid index if chronic use. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to pilocarpine or any component.","Acute iritis, acute anterior uveitis, or acute inflammatory conditions of the anterior chamber.","Narrow-angle glaucoma (unless considered for emergency treatment under specialist care).","Uncontrolled asthma, COPD, or other bronchospastic conditions.","Severe cardiovascular disease (bradycardia, hypotension, recent MI).","Gastrointestinal or urinary tract obstruction.","Concomitant use with other cholinergic agents due to additive toxicity."]
| Precautions | ["Risk of retinal detachment, especially in patients with pre-existing retinal disease or myopia.","May cause ciliary spasm, brow ache, and induced myopia.","Caution in patients with corneal abrasion or contact lens use due to miosis and accommodation effects.","Bronchospasm risk in patients with asthma or COPD.","Bradycardia, hypotension, and increased GI motility (use caution in peptic ulcer disease, urinary tract obstruction, or Parkinson's disease).","Systemic absorption can cause cholinergic toxicity."] |
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| Fertility Effects | No known adverse effects on fertility. Cholinergic agonism may affect uterine contractility; theoretical risk of implantation interference. |