Tropicamide

Tropicamide is a short-acting antimuscarinic drug applied directly to the eye. It blocks the muscle that narrows the pupil, so the pupil widens (mydriasis), and it relaxes the ciliary muscle that controls focusing (cycloplegia). The UK SmPC describes it simply as a topical mydriatic and cycloplegic. In practice it is used so that an optometrist or ophthalmologist can see the back of the eye, including the retina and optic nerve, and assess focusing errors. Its effects wear off much faster than those of atropine, usually within a few hours, which is why it is a common choice for routine dilated eye checks.

This listing is for a 1% solution in a multi-dose dropper bottle, sold as 1, 2, 3, 4 or 5 bottles. In the UK the drug is mainly found as Minims Tropicamide 0.5% and 1% single-use units made by Bausch & Lomb, along with generic single-dose containers, and each unit is thrown away after one use. The multi-dose bottle offered here is an imported generic presentation, so its packaging differs from UK products.

The SmPC for the 1% strength advises one drop, followed by a second drop five minutes later; one further drop may be added after 30 minutes if needed. Pressing gently on the inner corner of the eye for about a minute after each drop reduces the amount absorbed into the body, which matters especially for children. Other eye drops should be separated by at least five minutes, with any eye ointment applied last. In children this medicine may not relax focusing enough for testing, and strengths above 0.5% should not be used in small infants.

UK law classes these dilating drops as a prescription-only medicine (POM). They are mostly given in opticians’ practices, eye clinics and hospitals as part of an examination rather than issued for regular home use. The prescriber or examining clinician decides whether dilating drops are suitable and which strength to use. Because a bottle stays open for repeated use, it should be kept tightly closed, the dropper tip should not touch the eye or skin, and any solution left over should be discarded within the period stated on the label once opened.

These drops must not be used in narrow-angle glaucoma or where the drainage angle of the eye is narrow, because a dilated pupil can trigger an acute attack of angle-closure glaucoma. Eye pressure and angle depth should be checked first, particularly in older people who may have undiagnosed glaucoma. An inflamed eye absorbs more of the drug. Children, people with Down syndrome and anyone sensitive to belladonna-type medicines are at greater risk of whole-body effects, and the solution is harmful if swallowed, so hands should be washed after use. Effects may be stronger alongside other antimuscarinic medicines such as amantadine, some antihistamines, phenothiazines and tricyclic antidepressants.

After Tropicamide, blurred vision and sensitivity to light are expected and may last up to six hours, so you should not drive or operate machinery until your sight is clear. Other reported effects include stinging, eye pain or redness, raised eye pressure, headache, dizziness and nausea, and occasionally fainting or low blood pressure. Dry mouth, flushing, a fast heartbeat, confusion or unusual behaviour suggest the medicine has been absorbed into the body; in that case, or if the eye becomes painful with nausea and haloes around lights, get medical help straight away. Tropicamide is not suitable for injection.