Cyclopent Plus

Uses

Cyclopentolate is used mainly to produce mydriasis and cycloplegia for diagnostic purposes.

Phenylephrine is an alpha-1 adrenergic agonist used in the management of hypotension, generally in the surgical setting associated with the use of anesthetics.

Phenylephrine injections are indicated to treat hypotension caused by shock or anesthesia, an ophthalmic formulation is indicated to dilate pupils and induce vasoconstriction, an intranasal formulation is used to treat congestion, and a topical formulation is used to treat hemorrhoids. Off-label uses include situations that require local blood flow restriction such as the treatment of priapism.

Cyclopent Plus is also used to associated treatment for these conditions: Anterior Uveitis (AU)Allergic Rhinitis (AR), Anorectal discomfort, Cold, Common Cold, Common Cold/Flu, Congestion of the Conjunctivas, Conjunctivitis allergic, Cough, Cough caused by Common Cold, Eye allergy, Eye redness, Fever, Flu caused by Influenza, Headache, Headache caused by Allergies, Headache caused by Common Cold, Headache caused by Pollen Allergy, Hemorrhoids, Hypotension, Irritative cough, Itching of the nose, Itching of the throat, Laryngotracheitis, Nasal Congestion, Nose discomfort, Ocular Inflammation, Ocular Irritation, Paroxysmal Supraventricular Tachycardia, Pollen Allergy, Respiratory tract congestion, Respiratory tract irritation, Rhinopharyngitis, Rhinorrhoea, Seasonal Allergies, Shock, Cardiogenic, Sinus Congestion, Sinus pressure, Sinusitis, Sneezing, Sore Throat, Tracheobronchitis, Upper respiratory tract hypersensitivity reaction, site unspecified, Vasomotor Rhinitis, Aching caused by Flu caused by Influenza, Bronchial congestion, Itchy throat, Minor aches and pains, Watery itchy eyes, Airway secretion clearance therapy, Antihistamine, Dilatation of the pupil, Vasoconstrictor in regional analgesia therapy

How Cyclopent Plus works

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

Phenylephrine is an alpha-1 adrenergic agonist that mediates vasoconstriction and mydriasis depending on the route and location of administration. Systemic exposure to phenylephrine also leads to agonism of alpha-1 adrenergic receptors, raising systolic and diastolic pressure as well as peripheral vascular resistance. Increased blood pressure stimulates the vagus nerve, causing reflex bradycardia.

Dosage

Cyclopent Plus dosage

Adults and children over 1 year: 1 drop instilled in the eye(s), followed by a second drop 5 minutes later, if necessary. Drops should be administered 40 to 50 minutes prior to the procedure. To minimize systemic absorption, finger pressure should be applied to the lacrimal sac for 2 to 3 minutes following administration. Alternatively, the eyelids should be kept closed for 2 to 5 minutes following instillation. Patients with heavily pigmented irises may require larger doses. Complete recovery from mydriasis and cycloplegia should occur within 24 hours.

Side Effects

Blinding acute angle-closure glaucoma and raised intraocular pressure may occur during cyclopentolate therapy. The mydriasis may be reduced by the intraocular application of pilocarpine, physostigmine or isoflurophate. Transient burning sensation of the eye is more likely with the 0.5% solution. Systemic effects, resulting from excessive absorption from mucosal surfaces or from ingestion of the drug, may include xerostomia, flushing, tachycardia and urinary retention. More severe systemic effects are tachypnea, scarlatiniform rash, delirium, psychosis, fever, stupor, coma, respiratory failure and death.

Toxicity

Oral LD₅₀ in the rat is 4000 mg/kg and 960 mg/kg in the mouse. Symptoms of overdose include tachycardia, dizziness, dry mouth, behavioral disturbances, uncoordination and drowsiness.

Patients experiencing and overdose may present with headache, hypertension, reflex bradycardia, tingling limbs, cardiac arrhythmias, and a feeling of fullness in the head. Overdose may be treated by supportive care and discontinuing phenylephrine, chronotropic medications, and vasodilators. Subcutaneous phentolamine may be used to treat tissue extravasation.

Precaution

Cyclopentolate may cause an increase in intraocular pressure which if sustained, can potentially lead to irreversible loss of vision. The drug should be discontinued and the physician consulted immediately if eye pain, blurring of vision, rapid pulse or dizziness occurs. Patients may require the use of dark glasses following the application of cyclopentolate, due to photophobia associated with mydriasis. Patients should be advised to contact their physician if blurred vision and photophobia continue for more than 48 hours after discontinuing cyclopentolate. Systemic absorption of topical cyclopentolate from the nasal mucosal surfaces may result in systemic adverse effects. This is particularly the case in children, who are most susceptible to the drug's adverse effects. If signs of systemic toxicity appear, such as dry mouth, tachycardia or dizziness, the dosage schedule should be reduced or the drug discontinued

Interaction

Cyclopentolate may affect the action of concomitantly administered drugs such as: antihistamines, isoniazid, MAO inhibitors, phenothiazines, procainamide, disopyramide, propranolol, quinidine and tricyclic antidepressants. Anticholinergic agents, such as cyclopentolate, antagonize miosis and ciliary body contraction induced by cholinesterase inhibitors and cholinergic agonists.

Volume of Distribution

The volume of distribution of phenylephrine is 340L.

Elimination Route

Absorbed following ophthalmic administration.

Phenylephrine is 38% orally bioavailable. Clinically significant systemic absorption of ophthalmic formulations is possible, especially at higher strengths and when the cornea is damaged.

Half Life

Intravenous phenylephrine has an effective half life of 5 minutes and an elimination half life of 2.5 hours.

Clearance

Phenylephrine has an average clearance of 2100mL/min.

Elimination Route

86% of a dose of phenylephrine is recovered in the urine with 16% as the unmetabolized drug, 57% as the inactive meta-hydroxymendelic acid, and 8% as inactive sulfate conjugates.

Pregnancy & Breastfeeding use

pregnancy category C. Animal studies have not been reported. There are no controlled data in human pregnancy. Cyclopentolate ophthalmic is only recommended for use during pregnancy when benefit outweighs risk.

Contraindication

Cyclopentolate is contraindicated in patients with angle-closure glaucoma or in patients with shallow anterior chambers. Cyclopentolate should not be used in patients, especially children, who have previously experienced a severe systemic reaction to the drug, or in patients with hypersensitivity to any component of a cyclopentolate formulation.

Special Warning

Infants, young children and children with blond hair or blue eyes may be especially sensitive to the effects of cyclopentolate, increasing the chance of side effects during treatment. Use of cyclopentolate in children has been associated with psychotic reactions and behavioral disturbances.

Storage Condition

Store in a cool and dry place, away from light. Keep out of reach of children.

Innovators Monograph

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