Antimuscarinic mydriatic / cycloplegic Pregnancy: Safety in pregnancy and lactation not established; use only when considered essential. Data in pregnant women are limited and animal studies insufficient — as a precaution, preferably avoid during pregnancy. Breast-feeding: amount passing into breast milk unknown; infants can be very sensitive to anticholinergics, so the preparation should not be used during breastfeeding.

Cyclopentolate hydrochloride

Brand names: Mydrilate, Minims Cyclopentolate

Cyclopentolate hydrochloride is a topical antimuscarinic used to produce mydriasis and cycloplegia for diagnostic examination (notably cycloplegic refraction) and in the management of anterior uveitis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One or two drops as required

Route: Ophthalmic (instil dropwise into the eye)

Frequency: As required per indication (see notes)

Adults (including the elderly): instil one or two drops as required; maximum effect induced 30-60 minutes after instillation. For refraction and examination of the back of the eye: 1 drop, which may be repeated after five minutes, is usually sufficient. For anterior and posterior uveitis (if associated with signs of anterior uveitis) and for breakdown of posterior synechiae: 1-2 drops every 6-8 hours. Resistance to cycloplegia can occur in young children, patients with dark skin and/or dark irides, so the strength of cyclopentolate should be adjusted accordingly. Because of the risk of precipitating angle-closure glaucoma in the elderly and others prone to raised intraocular pressure, estimate anterior chamber depth before use. Children under 3 months: not recommended. Children 3 months-12 years: 1 drop of a 1% solution to each eye. Children 12 years-adult: 1 drop of 0.5% solution to each eye, repeated after 10 minutes if necessary. Children should be observed for 45 minutes after instillation. (Product characterised is Minims Cyclopentolate Hydrochloride 0.5% eye drops.)

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to cyclopentolate or to any excipient
Narrow-angle glaucoma or a tendency towards glaucoma (e.g. patients with a shallow anterior chamber)
Use in children with organic brain syndromes, including congenital or neuro-developmental abnormalities, particularly those predisposing to epileptic seizures

Side effects

Eye irritation, eye pain, ocular hyperaemia, blurred vision
Increased intraocular pressure
Dry mouth, constipation, nausea, vomiting, abdominal distension
Convulsions / seizures (reported in children); somnolence, dizziness
Tachycardia, bradycardia, palpitations; hallucination

Interactions

Other drugs with anticholinergic activity (anticholinergic effects could be increased — including antihistamines, butyrophenones, phenothiazines, tricyclic and tetracyclic antidepressants, amantadine, quinidine, disopyramide, oxybutynin)
Carbachol, pilocarpine, or ophthalmic cholinesterase inhibitors (cyclopentolate may interfere with their ocular anti-hypertensive action)

Clinical monograph

How it works

By blocking muscarinic receptors in the iris sphincter and ciliary muscle it paralyses accommodation and dilates the pupil, relieving ciliary spasm in inflammatory eye disease.

Prescribing in practice

Avoid in patients with untreated narrow anterior chamber angles, as pupil dilatation can precipitate acute angle-closure glaucoma.
Systemic antimuscarinic effects, including CNS disturbances, are a particular risk in infants and young children, in whom the lowest effective strength should be used.
Transient stinging, blurred vision and photophobia are expected after instillation.

Monitoring

Observe young children for systemic antimuscarinic effects such as drowsiness, confusion, flushing or behavioural change after administration.

Counselling the patient

Vision will be blurred and the eyes light-sensitive for several hours; do not drive until vision returns to normal.
Wearing sunglasses can help while the pupils remain dilated.
Apply gentle pressure to the inner corner of the eye after instillation, especially in children, to reduce systemic absorption.

Evidence & guidelines

Cyclopentolate is widely used for cycloplegic refraction, particularly in children, and as an adjunct in the treatment of anterior uveitis.

Reference: RCOphth; Royal College of Ophthalmologists paediatric guideline; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Drugs

Homatropine hydrobromide · Antimuscarinic mydriatic / cycloplegic

Pathways