Tropicamide
Tropicamide causes relatively rapid, short-duration mydriasis for ocular examination and selected postoperative management.
Group
Ophthalmic antimuscarinic mydriatic
Mechanism of Action
Blocks muscarinic effects in the iris sphincter and ciliary body, with stronger mydriatic than cycloplegic action.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Diagnostic mydriasis | Reference only | TOPICAL | Apply ophthalmic solution to the eye once or twice before examination; the source does not establish a universal drop count. | |
| Post-cataract pupil management | Reference only | TOPICAL | Every 8–12 h | Apply 2-3 times daily in the selected postoperative protocol; monitor pupil movement and IOP. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Diagnostic mydriasis | Reference only | TOPICAL | Apply ophthalmic solution to the eye once or twice before examination; the source does not establish a universal drop count. | |
| Post-cataract pupil management | Reference only | TOPICAL | Every 8–12 h | Apply 2-3 times daily in the selected postoperative protocol; monitor pupil movement and IOP. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Diagnostic mydriasis | Reference only | TOPICAL | Apply ophthalmic solution to the eye once or twice before examination; the source does not establish a universal drop count. | |
| Post-cataract pupil management | Reference only | TOPICAL | Every 8–12 h | Apply 2-3 times daily in the selected postoperative protocol; monitor pupil movement and IOP. |
Indications
- Funduscopic examination
- Selected post-cataract management
Contraindications
- Use cautiously in patients predisposed to angle-closure glaucoma or elevated IOP.
Interactions
- Other antimuscarinics may increase systemic or ocular effects.
Adverse effects
- Stinging and hypersalivation, particularly in cats.
- Can precipitate glaucoma in predisposed eyes and reduce Schirmer tear-test values temporarily.
Toxicity
Treat significant anticholinergic effects supportively and monitor IOP after excessive exposure.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Tropicamide ophthalmic solution 0.5% | Other | 5 mg / mL | TOPICAL |
| Tropicamide ophthalmic solution 1% | Other | 10 mg / mL | TOPICAL |
Monitoring and Administration
Perform baseline tear tests before application when needed; the drug can alter tear-test results for several hours.
Peak dilation is often 15-30 minutes; effects commonly recede over 6-12 hours. It is less reliable than atropine for painful cycloplegia.