Cyclopentolate Hydrochloride

Approved Indications:

• Diagnostic Procedures:
• Mydriasis (pupil dilation) for ophthalmic examinations
• Cycloplegia (paralysis of accommodation) during refraction testing, especially in pediatric patients
• Preoperative Use:
• As a pre-surgical mydriatic and cycloplegic agent before intraocular procedures
• Ocular Inflammation:
• Adjunctive treatment in uveitis, iritis, or postoperative inflammation to prevent posterior synechiae formation and reduce ciliary muscle spasm

Clinically Accepted Off-label Uses:

• Anterior uveitis management in conjunction with corticosteroids for pain relief and inflammation control
• Strabismus evaluation in children (to eliminate accommodation as a factor in esotropia)
• Assessment of accommodative esotropia during diagnostic workup

Route of Administration:
• Topical ophthalmic (eye drops)

For Mydriasis (Pupil Dilation):

• Adults & Children ≥3 months:
• Instill 1 drop of 0.5% or 1% solution into the eye(s), may repeat in 5–10 minutes if necessary

For Cycloplegia (Paralysis of Accommodation):

• Adults:
• 1 drop of 1% solution, repeated after 5–10 minutes
• Children (including infants >3 months):
• 1 drop of 0.5% or 1% solution, may repeat once after 5–10 minutes
• In infants, use 0.5% solution only and under strict supervision

Maximum Effect:

• Achieved within 30–60 minutes
• Duration of mydriasis: 24 hours or longer
• Duration of cycloplegia: 6–24 hours, sometimes up to 48 hours in children

Special Populations:

• Pediatrics (<3 months): Use cautiously; not routinely recommended due to increased risk of systemic toxicity
• Elderly: Increased sensitivity possible; monitor for anticholinergic effects
• Renal/Hepatic Impairment: No dose adjustment required (minimal systemic exposure), but caution is warranted in renal impairment due to anticholinergic metabolism

Administration Instructions:

• Apply gentle pressure to the nasolacrimal duct for 1–2 minutes after instillation to minimize systemic absorption
• Avoid contact with dropper tip to prevent contamination

Cyclopentolate is a competitive antagonist of muscarinic (M1–M5) acetylcholine receptors in the iris sphincter and ciliary body. By inhibiting parasympathetic innervation, it induces pupillary dilation (mydriasis) through relaxation of the iris sphincter muscle and cycloplegia by paralyzing the ciliary muscle, preventing accommodation. This facilitates detailed retinal examination and refraction assessment. Its central anticholinergic properties may also account for some systemic side effects in sensitive populations like children and the elderly.

• Absorption:
  Rapidly absorbed across the conjunctival and nasolacrimal mucosa into systemic circulation, especially in pediatric patients
• Onset of Action:
• Mydriasis: Within 15–45 minutes
• Cycloplegia: Within 25–75 minutes
• Duration of Action:
• Mydriasis: ~24 hours
• Cycloplegia: ~6–24 hours (prolonged in children)
• Distribution:
  Limited to ocular tissues with possible systemic distribution if not administered carefully
• Metabolism:
  Hepatic metabolism via cholinesterase hydrolysis
• Elimination:
  Excreted primarily in urine as metabolites
• Half-life:
  Short systemic half-life (~2–4 hours), but ocular effects persist longer

• Pregnancy:
  Classified as Pregnancy Category C (old FDA system). No adequate studies in pregnant women; use only if clearly needed. No known teratogenic effects reported in limited human data.
• Lactation:
  Unknown whether cyclopentolate is excreted in human milk. Because of its anticholinergic properties and potential CNS effects in infants, caution is advised.
• Recommendation:
  Use only if potential benefit outweighs risk; avoid repeated use in nursing mothers unless necessary.

• Primary Class: Anticholinergic (Parasympatholytic)
• Subclass: Mydriatic and Cycloplegic Ophthalmic Agent

• Hypersensitivity to cyclopentolate or any component of the formulation
• Narrow-angle (angle-closure) glaucoma or predisposition to it
• Untreated intraocular hypertension
• Use in infants <3 months of age (due to high risk of CNS toxicity)
• Severe paralytic ileus or myasthenia gravis (systemic exposure may exacerbate condition)

• CNS Effects in Children and Elderly:
• May cause confusion, hallucinations, hyperactivity, incoherent speech, or restlessness
• Monitor closely, especially after repeat dosing
• Increased Intraocular Pressure (IOP):
• May precipitate acute angle-closure glaucoma, especially in susceptible individuals
• Photophobia:
  Use sunglasses to reduce discomfort after dilation
• Systemic Anticholinergic Toxicity:
• Especially in children, may manifest as:
• Dry skin and mucous membranes
• Fever
• Tachycardia
• Flushing
• Urinary retention
• Seizures
• Use with caution in patients with cardiovascular disease, Down syndrome, GI disorders, and neurologic conditions

Common:

• Ocular: Burning, stinging, blurred vision, photophobia, lacrimation, conjunctival redness
• Systemic (especially in children): Dry mouth, flushing, drowsiness

Less Common:

• Nausea, tachycardia, headache, dizziness

Rare but Serious:

• Central nervous system effects: Hallucinations, disorientation, restlessness, incoherent speech
• Seizures: Reported mainly in infants or young children
• Angle-closure glaucoma
• Allergic reactions (rare): Rash, itching, angioedema

Severity & Timing:

• Systemic effects typically occur within 30–60 minutes of instillation and are dose-dependent

• Cholinergic drugs (e.g., pilocarpine): May antagonize the effects of cyclopentolate
• Other anticholinergic agents: Additive systemic anticholinergic burden (e.g., antihistamines, tricyclic antidepressants, antipsychotics)
• Glaucoma medications: May mask or interfere with IOP-lowering effects

CYP450 Involvement:

• Metabolism not significantly dependent on CYP isoenzymes; interactions primarily pharmacodynamic

• No recent major changes in dosing or indications
• New guidelines recommend cyclopentolate as a preferred agent for cycloplegic refraction in children, especially in strabismus and amblyopia assessment
• Increased emphasis on nasolacrimal occlusion during administration to reduce systemic absorption, especially in pediatric patients

• Temperature: Store at 15°C to 25°C (59°F to 77°F)
• Humidity and Light: Protect from excessive moisture and light
• Handling: Do not touch dropper tip to any surface to prevent contamination
• Refrigeration/Reconstitution: Not required; store in original packaging
• Shelf life: As per manufacturer's label; typically 24 months unopened