TROPICAMIDE
Clinical safety rating: safe
Animal studies have demonstrated safety
Antimuscarinic agent that blocks acetylcholine at muscarinic receptors in the ciliary muscle and sphincter muscle of the iris, resulting in mydriasis and cycloplegia.
| 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. |
| Molecular Weight | 284.35 |
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. |
| 1st trimester | Tropicamide is generally avoided in the first trimester unless clearly needed. Animal studies have shown embryo/fetal toxicity at high doses, but limited human data. |
| 2nd trimester | Use only if clearly indicated. No well-controlled studies in pregnant women, but potential anticholinergic effects may affect fetal heart rate. |
| 3rd trimester | Use near term may cause neonatal anticholinergic effects (e.g., tachycardia, constipation). Generally avoided unless benefit outweighs risk. |
Clinical note
Other anticholinergic drugs can have additive effects Contraindicated in patients with angle-closure glaucoma.
| Placental transfer | Tropicamide crosses the placenta in animal studies; human data limited but likely transfer occurs given molecular weight. |
| Breastfeeding | Ophthalmic use results in negligible systemic absorption, but theoretical risk of anticholinergic effects in the infant. If used, avoid prolonged or high-dose therapy and monitor infant for signs of anticholinergic toxicity (e.g., tachycardia, dry mouth, constipation). |
■ FDA Black Box Warning
None.
| Common Effects | mydriasis |
| Serious Effects |
Narrow-angle glaucomaHypersensitivity to tropicamide or any component of the formulationPatients with untreated narrow-angle glaucoma
| 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 |
| Food/Dietary | No known food interactions. However, as a topical ophthalmic agent, systemic absorption is minimal and dietary restrictions are not required. |
Loading safety data…
| Lactation Rating | L3 (Moderately Safe) - Limited data; potential for adverse effects, but low systemic absorption from ophthalmic use. |
| 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. |
| Fetal Monitoring | Maternal: monitor for systemic anticholinergic effects (tachycardia, dry mouth, blurred vision). Fetal: no specific monitoring required; if high doses used, monitor fetal heart rate. |
| Fertility Effects | No known effect on fertility. Ocular use is not expected to impair reproductive function. |
| Clinical Pearls | Tropicamide is a short-acting anticholinergic mydriatic and cycloplegic used for diagnostic ophthalmoscopy. Onset in 20-40 minutes, duration 4-6 hours. Use caution in patients with narrow-angle glaucoma or shallow anterior chamber depth. Systemic absorption can cause anticholinergic effects (dry mouth, tachycardia). In infants and elderly, risk of increased intraocular pressure. Reversal with pilocarpine if needed. |
| Patient Advice | This medication will cause blurred vision and sensitivity to light; wear sunglasses and avoid driving until effects wear off. · Do not touch the dropper tip to any surface to avoid contamination. · Remove contact lenses before use and wait at least 15 minutes before reinserting. · Report any eye pain, redness, or changes in vision to your doctor immediately. · Wash hands after administration to avoid accidental exposure to eyes or mouth. |