Tropicamide is a short-acting, antimuscarinic, anticholinergic agent used topically in ophthalmology as a mydriatic (pupil dilator) and cycloplegic (paralysis of accommodation). It is a synthetic derivative of tropic acid. In a 1% w/v concentration, it is primarily used for diagnostic mydriasis and cycloplegia during ophthalmic examinations, including fundoscopy and refraction. Its action is rapid and of relatively short duration, making it suitable for outpatient procedures.
Adult: For mydriasis/cycloplegia: Instill 1 or 2 drops of 1% solution into the conjunctival sac, 15-20 minutes before examination. May repeat once after 5 minutes if needed.
Note: 1. Wash hands. 2. Tilt head back. 3. Gently pull lower eyelid to form a pouch. 4. Instill prescribed drops without touching the dropper tip to eye or any surface. 5. Close eyes gently and apply pressure over the inner corner of the eye (nasolacrimal occlusion) for 1-2 minutes to minimize systemic absorption. 6. Wait 5 minutes before instilling any other eye drop.
Tropicamide competitively blocks the muscarinic acetylcholine receptors (specifically M3 and M4 subtypes) in the sphincter pupillae muscle of the iris and the ciliary muscle of the eye. This blockade inhibits the parasympathetic nerve-induced contraction of these muscles.
Pregnancy: Category C: Animal reproduction studies have shown an adverse effect, but no adequate and well-controlled studies in humans. Use only if potential benefit justifies potential risk to the fetus. Systemic absorption is minimal with proper technique.
Driving: DO NOT drive or operate machinery until vision clears (blurred vision and photophobia may persist for 4-8 hours, sometimes longer). Patient must be clearly advised.
| Other Anticholinergic Drugs (e.g., Atropine, Homatropine, Ipratropium) | Additive anticholinergic side effects (dry mouth, tachycardia, confusion). | Major |
| Tricyclic Antidepressants (e.g., Amitriptyline) | Additive anticholinergic effects, increased risk of intraocular pressure rise. | Moderate |
| Phenothiazines (e.g., Chlorpromazine) | Additive anticholinergic effects. | Moderate |
| MAO Inhibitors | Potentiation of anticholinergic effects. | Moderate |
| Sympathomimetics (e.g., Phenylephrine eye drops) | Additive mydriatic effect. Used together clinically but increases risk of IOP spike. | Moderate |
Same composition (Tropicamide (1% w/v)), different brands: