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Antimuscarinic cycloplegic / mydriatic (ophthalmic) Pregnancy: UK SPC section 4.6: 'There is insufficient evidence as to drug safety in pregnancy and lactation. This product should not be used during pregnancy unless it is considered essential by a physician.'

Cyclopentolate 1% Eye Drops (Mydrilate)

Brand names: Mydrilate, Minims Cyclopentolate

Cyclopentolate is a topical antimuscarinic (cycloplegic and mydriatic) agent used to dilate the pupil and paralyse accommodation for examination, cycloplegic refraction and as part of uveitis management.

Adult dose

Dose: Refraction / fundoscopy (adults and the elderly): one drop of 0.5% solution instilled into the eye, repeated after 15 minutes if necessary, approximately 40 minutes before examination; deeply pigmented eyes may require the use of a 1% solution. Uveitis, iritis and iridocyclitis (adults and the elderly): one or two drops of 0.5% solution instilled into the eye up to 4 times daily or as required; deeply pigmented eyes may require the use of a 1% solution
Route: Ophthalmic (eye drops instilled into the eye)
Frequency: Refraction / fundoscopy: one drop, repeated once after 15 minutes if necessary, about 40 minutes before examination. Uveitis / iritis / iridocyclitis: up to 4 times daily or as required
STRENGTH SCOPE (read first): this card is sourced from the UK SPC for Mydrilate 1.0% Eye Drops (eMC product 1724). Its section 4.2 prints the standard ADULT regimens as 0.5% solution and gives 1% for adults only as the escalation for deeply pigmented eyes ('Deeply pigmented eyes may require the use of a 1 % solution'), with no separate adult drop count or frequency for 1%. No adult 1% drop count has been inferred. INDICATIONS (section 4.1, verbatim): '(i) Diagnostic purposes for fundoscopy and cycloplegic refraction. (ii) Dilating the pupil in inflammatory conditions of the iris and uveal tract.' NO MAXIMUM DOSE is printed in the SPC for either indication, so none is given. ONSET AND DURATION (section 4.2): 'Maximal cycloplegia is achieved within 15 - 45 minutes of instillation and lasts on average about 20 minutes. Recovery normally takes place in about 4 hours, but very occasionally some effect persists for up to 24 hours.' Mydriasis: 'an average pupil diameter of 7 mm is usually reached 15 - 30 minutes after instillation of one drop of 0.5 % solution. Complete recovery from the mydriatic effect generally occurs spontaneously in not more than 20 hours.' REDUCING SYSTEMIC ABSORPTION (section 4.4): 'the lacrimal sac should be compressed at the medial canthus by digital pressure for at least two minutes after instillation of the drops.' ELDERLY: 'No specific information on the use of this product in the elderly is available.' Not to be used while soft contact lenses are worn (contains benzalkonium chloride).

Paediatric dose

Dose: Refraction / fundoscopy, 1% solution: children 6-16 years - one drop instilled into the eye, repeated after 15 minutes if necessary, approximately 40 minutes before examination; children under 6 years - one or two drops, repeated after 15 minutes if necessary, approximately 40 minutes before examination
Route: Ophthalmic (eye drops instilled into the eye)
Frequency: Repeat once after 15 minutes if necessary, approximately 40 minutes before examination
FIXED DROP COUNTS, NOT WEIGHT-BASED - dosePerKg is null; do not derive a per-kg figure. SPC section 4.2, verbatim: 'Children 6-16 years: One drop of 1 % solution instilled into the eye, repeated after 15 minutes if necessary, approximately 40 minutes before examination'; 'Children under 6 years: One or two drops of 1 % solution instilled into the eye, repeated after 15 minutes if necessary, approximately 40 minutes before examination.' UVEITIS, IRITIS AND IRIDOCYCLITIS in children: 'At the discretion of the physician' - no figure is printed. FIRST THREE MONTHS OF LIFE, verbatim: 'Do not use during the first three months of life due to possible association between the cycloplegia produced and the development of amblyopia and also the increased risks of systemic toxicity in neonates.' Section 4.4: 'Extreme caution is advised for use in children and individuals susceptible to belladonna alkaloids because of the increased risk of systemic toxicity.' Use is contraindicated in children with organic brain syndromes, including congenital or neuro-developmental abnormalities, particularly those predisposing to epileptic seizures.

Dose adjustments

Renal

No renal dose adjustment is stated in the UK SPC sections retrieved (section 4.2 gives no renal guidance).

Hepatic

No hepatic dose adjustment is stated in the UK SPC sections retrieved (section 4.2 gives no hepatic guidance).

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Use in narrow-angle glaucoma or those with a tendency towards glaucoma e.g. patients with a shallow anterior chamber
  • Hypersensitivity to cyclopentolate hydrochloride, benzalkonium chloride or any other components of the formulation
  • Contains benzalkonium chloride and should not be used whilst soft contact lenses are being worn
  • Use in patients with paralytic ileus
  • Use in children with organic brain syndromes, including congenital or neuro-developmental abnormalities, particularly those predisposing to epileptic seizures
  • Do not use during the first three months of life (possible association between the cycloplegia produced and the development of amblyopia, and increased risk of systemic toxicity in neonates) - section 4.2

Side effects

  • All frequencies 'not known' (SPC section 4.8):
  • Psychiatric / nervous system: abnormal behaviour, psychotic disorders (reported in the paediatric population); dizziness; convulsions and partial seizures (reported in children, though cases reported to date have been low in number or isolated)
  • Eye: eye pain, increased intraocular pressure, eye oedema, eye irritation (stinging), ocular hyperaemia, conjunctivitis (these last four following prolonged administration); photophobia (secondary to pupillary dilation)
  • Cardiac / vascular: bradycardia, tachycardia, palpitations, arrhythmia, cardiopulmonary failure (reported in the paediatric population); flushing
  • Gastrointestinal: dry mouth, vomiting, gastrointestinal hypomotility and constipation, abdominal distension (reported in infants), necrotising enterocolitis (reported in preterm infants)
  • Skin: dry skin, skin rash (reported in the paediatric population)
  • Renal / urinary: urinary urgency, urinary retention, dysuria; general: gait disturbance
  • Atropine-like effects have been reported as side-effects (section 4.4)

Interactions

  • The effects of anti-muscarinic agents may be enhanced by concomitant administration of other drugs with anti-muscarinic properties such as some antihistamines, butyrophenones, phenothiazines, tricyclic antidepressants and amantadine (SPC section 4.5)

Monitoring

  • Before use, an estimate of the depth of the anterior chamber should be made because of the risk of precipitating angle-closure glaucoma in the elderly and others prone to raised intraocular pressure, particularly if therapy is likely to be intense or protracted
  • Caution in patients with prostatic enlargement, coronary insufficiency or cardiac failure, or ataxia
  • Extreme caution in children and individuals susceptible to belladonna alkaloids because of the increased risk of systemic toxicity
  • Use with caution in an inflamed eye - the hyperaemia greatly increases the rate of systemic absorption through the conjunctiva
  • Preterm infants: use of mydriatic agents has been associated with feed intolerance, abdominal distention, increased gastric aspirate and rare cases of necrotising enterocolitis; convulsions have been reported in children
  • Oral toxicity: patients should be warned of the oral toxicity of this preparation, advised to wash their hands after use, and if it is accidentally swallowed to seek medical attention

Clinical monograph

How it works

It competitively blocks muscarinic receptors on the iris sphincter and ciliary muscle, producing pupil dilatation and temporary paralysis of accommodation.

Prescribing in practice

  • Systemic antimuscarinic toxicity (central nervous system disturbance, flushing, tachycardia) can occur particularly in infants and young children, so use the lowest effective strength and apply nasolacrimal occlusion.
  • May precipitate an acute rise in intraocular pressure in eyes with a narrow anterior chamber angle, so caution is needed in those predisposed to angle-closure glaucoma.
  • Effects on vision and accommodation can persist for some time, longer than with shorter-acting mydriatics.

Monitoring

Observe young children for signs of systemic antimuscarinic effects after instillation, and assess the eye for any pressure rise in those with narrow angles.

Counselling the patient

  • Your vision will be blurred and you may be sensitive to light for several hours, so do not drive until it has worn off.
  • Wear sunglasses and report any eye pain, redness or visual disturbance.
  • In children, press gently on the inner corner of the eye after drops to reduce absorption.

Evidence & guidelines

Cyclopentolate is a long-established cycloplegic supported by standard ophthalmic practice and the relevant SPC.

Reference: RCOphth Refraction Guidelines; Mydrilate SPC; 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).

Related

Curated clinical cross-links plus same-class fallbacks.

Pathways