Cyclopentolate hydrochloride may increase intraocular pressure. A considerable burning sensation usually occurs following instillation of a 1 or 2% solution of the drug; the 0.5% solution is less irritating. This burning sensation is transient and patients should be advised of the likelihood of its occurrence; children may be particularly distressed by this local discomfort.
Topical application of cyclopentolate hydrochloride to the eye may cause adverse systemic antimuscarinic effects , especially with frequent or prolonged topical instillation of the drug and in children. Use of cyclopentolate hydrochloride has been associated with adverse CNS reactions (e.g., CNS disturbances, psychotic reactions). Younger patients are especially prone to develop CNS disturbances, but such effects may occur at any age, particularly with the more concentrated preparations. Psychotic reactions and behavioral disturbances have been reported in children, especially with the 2% solution. These reactions develop within about 30-45 minutes after instillation of the drug and have been manifested as ataxia, incoherent speech, restlessness, hyperactivity, seizures, aimless wandering, irrelevant talking, hallucinations, disorientation as to time and place, failure to recognize people, amnesia, and tachycardia. Rarely, adults may develop comparable reactions.
An allergic reaction may occur following repeated use of cyclopentolate hydrochloride. The reaction is characterized by persistent irritation that develops within minutes of instillation of the drug; while vision is blurred and the eyes are diffusely red, itching is not common. The corneal surface is uniformly covered with tiny, superficial punctate epithelial lesions; with repeated reactions, the lacrimal drainage system may become occluded.