Tropicamide
Also known as: Mydriacyl
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Mydriasis and cycloplegia for intraocular examination | 1 drop per eye | topical | repeat after 20-30 min if necessary | — | 🌍 EU |
- Mydriasis and cycloplegia for intraocular examination: Duration of action is 2-12 hours.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Mydriasis and cycloplegia for intraocular examination | 1 drop per eye | topical | repeat after 20-30 min if necessary | — | 🌍 EU |
- Mydriasis and cycloplegia for intraocular examination: Duration of action is 4-9 hours. May cause salivation.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Tropicamide is a synthetic, short-acting anticholinergic agent primarily used for mydriasis (pupil dilation) and cycloplegia (paralysis of the ciliary muscle). It is considered the mydriatic of choice for intraocular examinations due to its rapid onset of action (20-30 minutes) and relatively short duration.
Clinical Pearl: Tropicamide is more effective as a mydriatic than as a cycloplegic. Therefore, it is less effective than atropine in relieving ciliary body muscle spasms associated with uveitis.
Mechanism of action
Tropicamide acts as a competitive antagonist of acetylcholine at muscarinic receptors.
Acetylcholine inhibition at the iris sphincter muscle → relaxation of the sphincter → mydriasis (pupil dilation). Acetylcholine inhibition at the ciliary body muscles → paralysis of accommodation → cycloplegia.
Safety & warnings
Contraindications
- Glaucoma (may increase intraocular pressure)
Adverse effects
- Salivation (particularly in cats, though less marked than with atropine)
- Transient stinging upon application
- Photophobia (due to pupil dilation)
Precautions
Warning: Use with extreme care in patients with lens luxation.
Normal safety and handling precautions should be observed. Avoid contamination of the dropper tip.
Monitoring
- Intraocular pressure (IOP)
- Pupillary light reflex
- Resolution of mydriasis
Pharmacokinetics
Half-life
Absorption
Rapid onset of action following topical application (20-30 minutes).
Distribution
Local distribution within the anterior segment of the eye.
Metabolism
Systemic absorption is minimal; locally metabolized by tissue esterases.
Elimination
Cleared locally and via systemic circulation if absorbed.
Overdose
Systemic toxicity is rare with standard topical ophthalmic use. However, excessive administration or ingestion could theoretically lead to systemic anticholinergic signs such as tachycardia, dry mucous membranes, ileus, and urinary retention. Treatment is generally supportive.
Available products
Formulations
- Ophthalmic solution: 0.5%
- Ophthalmic solution: 1%
Human-labeled
- Mydriacyl 0.5% ophthalmic solution
- Mydriacyl 1% ophthalmic solution
- Tropicamide 0.5% ophthalmic solution
- Tropicamide 1% ophthalmic solution
Regulatory status
Human approved products used off-label in veterinary medicine.
POM (Prescription Only Medicine)
POM-V (Prescription Only Medicine - Veterinarian)
No regulatory data for: 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature. Protect from light. Single-use vials should be discarded immediately after use.
Client information
Administer eye drops exactly as directed by your veterinarian.
- Your pet's pupils will be widely dilated, making them very sensitive to bright light. Keep them out of direct sunlight until their pupils return to normal size.
- Cats may drool or foam at the mouth shortly after the drops are applied. This is a normal reaction to the bitter taste of the medication draining into the back of the throat and usually resolves quickly.
- Do not touch the dropper tip to the eye or any other surface to prevent contamination.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.