CYCLOGYL 1% EYE DROPS

Indications

• Ophthalmic examinations requiring mydriasis
• Treatment of uveitis
• Cycloplegia for refraction

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidelines.

Adults: Refer to the BNF for appropriate dosing guidelines.

Mechanism of action

Cyclopentolate exerts its effects by blocking muscarinic receptors, which leads to pupil dilation (mydriasis) and prevents accommodation for near vision (cycloplegia). This action is achieved through the relaxation of the sphincter of the iris and the ciliary muscles.

Pharmacodynamics

As an anti-muscarinic agent, cyclopentolate belongs to the same class as atropine and scopolamine. It effectively inhibits the action of acetylcholine at muscarinic receptors in the eye, resulting in rapid and intense cycloplegic and mydriatic effects. These effects typically reach their peak within 15 to 60 minutes after application and usually resolve within 24 hours, although recovery may be prolonged in individuals with darker irises.

Pharmacokinetics

Cyclopentolate is administered topically in the form of eye drops. Its onset of action is rapid, with peak effects occurring within 15 to 60 minutes. The duration of action varies, generally lasting for about 24 hours. The pharmacokinetics may be influenced by factors such as iris pigmentation, which can affect both the onset and duration of action.

Adverse effects

• Photophobia
• Increased intraocular pressure
• Dry mouth
• Blurred vision
• Tachycardia
• Dizziness

Interactions

• Clozapine+cyclopentolate: Unknown (additive effect)
• Antipsychotics, second-generation+cyclopentolate: Unknown (additive effect)

Precautions

• Use with caution in patients with glaucoma
• Caution in patients with a history of cardiovascular disease
• Not recommended for use in infants under 6 months of age

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Cyclopentolate should be used during pregnancy only if clearly needed.

Breast-feeding

Cyclopentolate is excreted in breast milk. Caution should be exercised when cyclopentolate is administered to a nursing mother.

Storage

Store below 25°C. Keep out of reach of children. Protect from light.

Formulations

• Eye drops: 1% solution
• Eye drops: 0.5% solution

Indications

• Dry eye conditions
• Cycloplegia
• Anterior uveitis

Dosage

Children: For children aged 3 months to 11 years: Apply 1 drop of 0.5% eye drops 30–60 minutes before examination. For dry eye treatment, apply 1 drop 2–4 times a day

Adults: For dry eye conditions, consult product literature as dosage may vary. Generally, instill 1 drop of 0.5% to 1% solution into the affected eye(s) 2–4 times a day depending on the severity of symptoms.

Mechanism of action

Cyclopentolate hydrochloride acts as a non-selective antagonist of muscarinic acetylcholine receptors. By blocking these receptors, it prevents the action of acetylcholine, leading to relaxation of the ciliary muscle and dilation of the pupil (mydriasis). This mechanism facilitates ophthalmic examinations by reducing eye accommodation and enhancing visibility of the internal structures of the eye.

Pharmacodynamics

The pharmacodynamics of cyclopentolate are characterized by its ability to induce mydriasis and cycloplegia. The onset of mydriatic effect occurs within 30 minutes following instillation, lasting up to 24 hours. The duration of cycloplegic effects can vary depending on the dose and individual patient factors, with effects typically lasting several hours.

Pharmacokinetics

Cyclopentolate hydrochloride is administered topically as eye drops, leading to localized effects with minimal systemic absorption. After administration, peak plasma concentrations are achieved quickly, with a rapid onset of action. The drug is primarily metabolized in the liver, and its elimination half-life is influenced by the route of administration and individual metabolic factors. It is essential to note that systemic side effects can occur, particularly in pediatric and elderly populations.

Adverse effects

• Abdominal distension (in children)
• Arrhythmias
• Behavioural abnormalities (in children)
• Cardiac respiratory distress (in children)
• Conjunctivitis
• Constipation
• Dry mouth
• Oedema (on prolonged administration)
• Flushing
• Gastrointestinal disorders
• Hyperaemia (on prolonged administration)
• Mydriasis
• Palpitations
• Psychotic disorder (in children)
• Staggering
• Urinary disorders
• Vomiting

Precautions

• Systemic side effects can occur, particularly in children and the elderly.
• Preservative-free formulations are preferred for frequent and chronic applications.

Pregnancy

There are no adequate and well-controlled studies in pregnant women. Use only if clearly needed.

Breast-feeding

Caution is advised; monitor for side effects in the infant.

Storage

Store in a cool, dry place away from light. Once opened, use within the designated time frame as per product guidelines.

Formulations

• {'name': 'Cyclopentolate hydrochloride 0.5% eye drops', 'strength': '5 mg per 1 ml', 'form': 'unit dose vial', 'volume': '0.5 ml'}
• {'name': 'Cyclopentolate hydrochloride 1% eye drops', 'strength': '10 mg per 1 ml', 'form': 'unit dose vial', 'volume': '0.5 ml'}
• {'name': 'Mydrilate 0.5% solution', 'strength': '5 mg per 1 ml', 'form': 'solution', 'volume': '5 ml'}
• {'name': 'Mydrilate 1% solution', 'strength': '10 mg per 1 ml', 'form': 'solution', 'volume': '5 ml'}

Mechanism of action

By blocking muscarinic receptors, cyclopentolate produces dilatation of the pupil (mydriasis) and prevents the eye from accommodating for near vision (cycloplegia).

Pharmacodynamics

Cyclopentolate is an anti-muscarinic in the same class as atropine and scopolamine. Cyclopentolate blocks the receptors in the muscles of the eye (muscarinic receptors). These receptors are involved controlling the pupil size and the shape of the lens. Cyclopentolate thus induces relaxation of the sphincter of the iris and the ciliary muscles. When applied topically to the eyes, it causes a rapid, intense cycloplegic and mydriatic effect that is maximal in 15 to 60 minutes; recovery usually occurs within 24 hours. The cycloplegic and mydriatic effects are slower in onset and longer in duration in patients who have dark pigmented irises.