[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Mydriatics and cycloplegics](https://durgical.com/en/pharmacology/classes/mydriatics-and-cycloplegics/) › Cyclopentolate

# Cyclopentolate

## Mydriatics and cycloplegics?

Mydriatics and cycloplegics

An antimuscarinic eye drop that paralyses focusing and dilates the pupil, used to measure refraction. Stronger and longer than tropicamide.

Updated Nov 1, 2026

## Quick facts

**Group**
[Mydriatics and cycloplegics](https://durgical.com/en/pharmacology/classes/mydriatics-and-cycloplegics/)

**Target**
Muscarinic acetylcholine receptors of the iris sphincter and ciliary muscle

**Used for**
Cycloplegic refraction

**Key effects**
Stinging · Blurred vision and light sensitivity

**Monitor**
Behaviour · Feeding tolerance

**ATC**
S01FA04

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Cyclopentolate blocks muscarinic receptors of the iris sphincter and the ciliary muscle. With accommodation paralysed, the true refractive error can be measured, which matters most in children, who focus strongly. It acts faster and wears off sooner than atropine, but more slowly than tropicamide.

- Cyclopentolate blocks muscarinic receptors in the eye
- The ciliary muscle relaxes: accommodation is paralysed
- The pupil widens; true refraction can be measured

## Indications

- Cycloplegic refraction (measuring refractive error with accommodation paralysed) [Refractive errors and presbyopia →](https://durgical.com/en/conditions/refractive-errors-and-presbyopia/)
- Pupil dilation for eye examination

## Adverse effects

### Common

- Stinging, irritation, redness
- Blurred vision and light sensitivity
- Conjunctivitis, keratitis
- Fast heart rate

### Serious (rare, important)

- Psychosis-like reactions, behaviour changes and seizures, mostly in children
- In infants: central nervous system and cardiopulmonary effects, feeding intolerance
- Rise in intraocular pressure
- Severe poisoning: coma, medullary paralysis, death

## Contraindications

- Hypersensitivity to any component
- Caution: Down syndrome; children with spastic paralysis or brain damage

## Key interactions

**Carbachol, pilocarpine or ophthalmic cholinesterase inhibitors**
Cyclopentolate can counteract their pressure-lowering effect

## What is monitored

- Behaviour, heart rate and breathing in children
- Feeding tolerance in infants after the exam

## Administration and safety

- For the eye only; never injected.
- Pressure on the lacrimal sac for a few minutes after the drop reduces systemic absorption.
- In infants, feeds are held for four hours after the examination.

## Pregnancy and breastfeeding

No animal reproduction studies exist; it is used in pregnancy only if clearly needed.

## Nursing care

- Before giving it to a child, check for Down syndrome, spastic paralysis or brain injury.
- Watch for restlessness, confusion, hallucinations, flushing or a fast pulse after the drops.
- Warn about blurred vision and glare; no driving while dilated; sunglasses help.

## Pharmacokinetics

**Onset and duration**
Maximal cycloplegia about 25–75 minutes after the drop; focusing usually recovers within 6–24 hours, while full pupil recovery can take several days

## Memory aid

CYCLOpentolate paralyses the CYCLOplegic muscle (ciliary): it is the refraction drop, while tropicamide is the fundus drop.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is cyclopentolate used before measuring refraction in children?

It paralyses accommodation, so the true refractive error can be measured.

## Which infant-specific precaution follows a cyclopentolate exam?

Feeds are withheld for four hours because of feeding intolerance.

## Which systemic toxicity is typical of antimuscarinic eye drops in children?

Central nervous system effects: agitation, psychosis-like reactions and seizures, with a fast pulse.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/cyclopentolate/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 2

- [Tropicamide](https://durgical.com/en/pharmacology/tropicamide/)
- [Atropine](https://durgical.com/en/pharmacology/atropine/)

## Related conditions 1

- [Refractive errors and presbyopia](https://durgical.com/en/conditions/refractive-errors-and-presbyopia/)

[← Back to the class: Mydriatics and cycloplegics](https://durgical.com/en/pharmacology/classes/mydriatics-and-cycloplegics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - CYCLOPENTOLATE HYDROCHLORIDE solution/ drops](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ad85b220-6003-4a78-b900-5195ceaf0fd5) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=S01FA04) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/cyclopentolate/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/cyclopentolate/