TROPICAMIDE

Clinical safety rating: safe

Animal studies have demonstrated safety

How it works

Antimuscarinic agent that blocks acetylcholine at muscarinic receptors in the ciliary muscle and sphincter muscle of the iris, resulting in mydriasis and cycloplegia.

What the body does with it

Metabolism	Primarily hepatic via ester hydrolysis; metabolites include tropic acid and tropine.
Excretion	Primarily renal excretion of unchanged drug and metabolites; approximately 30% unchanged in urine within 6 hours; minor biliary/fecal elimination (<5%).
Half-life	Terminal elimination half-life is approximately 2 hours; clinically, mydriasis and cycloplegia persist for 4-8 hours despite rapid plasma clearance.
Protein binding	Approximately 40% bound to plasma proteins, primarily albumin.
Volume of Distribution	Approximately 0.2 L/kg; indicates distribution primarily into extracellular fluid.
Bioavailability	Bioavailability after ophthalmic administration is low due to limited systemic absorption; systemic bioavailability is negligible for clinical relevance; oral bioavailability not applicable as not administered systemically.
Onset of Action	Ophthalmic: Mydriasis within 20-40 minutes, cycloplegia within 30-60 minutes after topical instillation.
Duration of Action	Mydriasis lasts 4-6 hours, cycloplegia lasts 6-8 hours; maximal effect at 1-2 hours; recovery may take up to 24 hours in elderly or darkly pigmented irides.

Classification & Brands

Dosing & administration

1-2 drops of 0.5% or 1% solution topically in the eye(s), repeated in 5 minutes if needed for maximal effect; for cycloplegic refraction, 1-2 drops of 1% solution repeated in 5 minutes.

Dosage form	SOLUTION/DROPS
Renal impairment	No dose adjustment required for renal impairment as systemic absorption is minimal.
Liver impairment	No dose adjustment required for hepatic impairment as systemic absorption is minimal.
Pediatric use	Infants and children: 1-2 drops of 0.5% solution topically in the eye(s), repeated in 5 minutes if needed; for cycloplegic refraction in children, 1-2 drops of 1% solution may be used.
Geriatric use	No specific dose adjustment; use lowest effective concentration due to increased risk of systemic anticholinergic effects and intraocular pressure elevation.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Other anticholinergic drugs can have additive effects Contraindicated in patients with angle-closure glaucoma.

Breastfeeding	Minimal systemic absorption after ocular use; M/P ratio not established. Unlikely to affect breastfed infant. Use with caution.
Teratogenic Risk	No evidence of teratogenic risk in animal studies or human case reports. Systemic absorption after ocular administration is minimal. Theoretically, anticholinergic effects at high doses could cause fetal tachycardia or reduced amniotic fluid. First trimester: no known risk. Second trimester: no known risk. Third trimester: possible fetal tachycardia with maternal systemic exposure.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Common Effects	mydriasis
Serious Effects

Absolute Contraindications

["Narrow-angle glaucoma","Hypersensitivity to tropicamide or any component of the formulation"]

Clinical Precautions

Precautions

["Caution in patients with increased intraocular pressure or narrow-angle glaucoma","May cause blurred vision and photosensitivity; avoid driving or hazardous activities until effect subsides","Systemic effects may occur with excessive use, especially in children and elderly"]

Clinical Tips & Counseling

Drug interactions

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