PHARMACOLOGICAL ACTION: Cyclopentolate hydrochloride is an anticholinergic with actions similar to atropine. It blocks the responses of the sphincter muscle of the iris and the accommodative muscle of the ciliary body to cholinergic stimulation producing mydriasis and cycloplegia. It acts rapidly, but has a shorter duration than atropine. Phenylephrine hydrochloride is a sympathomimetic agent with mainly direct effects on alpha-adrenergic receptors. The combination of cyclopentolate and phenylephrine induces mydriasis of short duration considerably greater than that of either drug in high concentration alone with little or no cycloplegia. 30 Minutes after instillation a mean increase of 3,5 to 4,0 mm in pupil size and a mean tonometric change (7,5 Schiotz) of no more than about 1,0 mm have been typically observed.
INDICATIONS: For producing a rapid and profound mydriasis of the irises for funduscopic examination.
CONTRA-INDICATIONS: Narrow-angle or closed-angle glaucoma. Patients with anatomically narrow angles. Treatment with a monoamine oxidase inhibitor or within 10 days of stopping such treatment. Hypersensitivity to any of the ingredients.
WARNINGS: For topical use only not for injection. The use of this combination may have an adverse effect on individuals suffering from cardiovascular disease, hypertension and hyperthyroidism; and it may cause CNS disturbances. Small infants are especially prone to CNS and cardiopulmonary side-effects from systemic absorption of cyclopentolate. As the possibility of adverse effects on the corneal permeability and the danger of disruption of the corneal epithelium with prolonged or repeated usage of benzalkonium chloride preserved ophthalmological preparations cannot be excluded, regular ophthalmological examination is required. Caution should be exercised in the use of benzalkonium chloride preserved topical medication over an extended period in patients with extensive ocular surface disease.
The use of cyclopentolate has been associated with psychotic reactions and behavioural disturbances particularly in children. This drug also produces reactions similar to those of other anticholinergic drugs: However, the central nervous system manifestations as noted above are more common.
PATIENT WARNING: Patients should be advised not to drive or engage in hazardous activities while pupils are dilated. Patients may experience sensitivity to light and should protect eyes in bright illumination during dilation. Parents should be warned not to get this preparation in their child's mouth and to wash their own and the child's hands following administration.
DOSAGE AND DIRECTIONS FOR USE: For funduscopy, instill one drop in each eye every five to ten minutes, not to exceed three times, to produce rapid mydriasis, permitting ready visual access to the: fundus. Heavily pigmented irises may require larger doses. To minimize absorption in premature and small infants, apply pressure over the nasolacrimal sac for two to three minutes following instillation. Observe infants closely for at least 30 minutes.
SIDE EFFECTS AND SPECIAL PRECAUTIONS: SIDE EFFECTS: Increased intra-ocular pressure. Systemic reactions may be produced particularly in children. Systemic absorption may be minimised by compressing the lacrimal sac for two to three minutes after instillation. A transient stinging may be observed on instillation. Hypersensitivity as conjunctivitis may occur.
SPECIAL PRECAUTIONS: Use with caution in the elderly and others where an increased intra-ocular pressure may occur. To avoid inducing angle closure glaucoma, an estimation of the depth of the angle of the anterior chamber should be made. The effects of phenylephrine are enhanced by guanethidine and to a lesser extent by reserpine, methyldopa and tricyclic antidepressants. The effect of long-term use of this preparation has not been established, therefore it should be restricted to short-term use.
KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT: Central nervous system manifestations including ataxia, incoherent speech, restlessness, hallucinations, hyperactivity; seizures, disorientation as to time and place and failure to recognize people. Other toxic manifestations of anticholinergic drugs are tachycardia, hyperpyrexia, vasodilatation, urinary retention, diminished gastrointestinal motility and decreased secretion in salivary and sweat glands, pharynx, bronchii and nasal passages. Severe manifestations of toxicity include coma, medullary paralysis and death.
TREATMENT: In case of severe manifestations of toxicity physostigmine salicylate may be given by slow intravenous injection. The paediatric dose is 0,5 mg repeated every five minutes to a maximum dose of 2,0 mg if no cholinergic symptoms are produced: The adult dose is 2,0 mg followed by 1-2 mg after 20 minutes if necessary.
IDENTIFICATION: A clear, colourless to pale yellow liquid.