Disclaimer to the On-line Edition
This Manual has been designed for use in the NICU at London Health Sciences Centre (LHSC), London, Ontario, Canada, and represents clinical practice at this institution. The information contained within the Manual may not be applicable to other centres. If users of this Manual are not familiar with a drug, it is recommended that the official monograph be consulted before it is prescribed and administered. Any user of this information is advised that the contributors, Editor and LHSC are not responsible for any errors or omissions, and / or any consequences arising from the use of the information in this Manual.


  • combination product which contains cyclopentolate 0.2% AND phenylephrine 1%. This combination results in MYDRIASIS (dilation of the pupil), CYCLOPLEGIA (paralysis of accommodation) and CONSTRICTION of conjunctival arterioles. This specific combination has been recommended as the agent of choice to dilate the pupils of low-weight infants


  • to dilate the pupils of infants for retinal examination



  • cyclopentolate blocks the action of acetylcholine. This anticholinergic effect results in MYDRIASIS and CYCLOPLEGIA
  • maximum mydriasis and maximum cycloplegia occur about 15-60 minutes following topical application to the eye. Both effects generally last about 24 hours

Side Effects

  • burning sensation when a 1%, or even a 0.5%, solution is used
  • topical administration may result in adverse systemic effects (eg. inhibition of GI tract motility, urinary retention, tachycardia, relaxation of smooth muscle in bronchi and bronchioles, CNS stimulation)



  • acts directly on adrenergic receptors in the eye to produce contraction of the dilator muscle of the pupil (thus producing mydriasis) and constriction of arterioles in the conjunctiva
  • only slight relaxation of the ciliary muscle is produced therefore substantial cycloplegia is not likely to occur

Side Effects

  • may produce transient burning or stinging when applied topically to the eye
  • may produce systemic sympathomimetic effects (eg. palpitation, tachycardia, pallor or blanching, trembling, increased perspiration, hypertension)

Nursing Precautions

  • small infants are especially prone to the CNS and cardiopulmonary side effects from systemic absorption of cyclopentolate. Infants should be watched closely for at least 60 minutes for signs of vasoconstriction (pallor, blanching, mottling), tachycardia, increased blood pressure and apneic spells
  • there have been reports of adverse effects following the instillation of CYCLOMYDRIL(R) in 2 infants from this unit
  • feeding intolerance has also been associated with the use of this product. This may persist for up to 4 hours or more
  • to minimize systemic absorption it is recommended that pressure be applied over the nasolacrimal sac for 2 to 3 minutes following instillation
  • maximum mydriasis and cycloplegia occur 15-60 minutes following instillation; these effects generally last about 24 hours but mydriasis may persist for several days. The infant's pupil size should be monitored for 24 hours after instillation of the drops and exposure to bright light should be avoided
  • phenylephrine is subject to oxidation. DO NOT use the solution if it is brown or contains a precipitate


  • 1 drop to each eye; REPEAT in 10 minutes (approximately 60 minutes before eye examination)


  • CYCLOMYDRIL(R) ophthalmic solution, 5mL (NOTE: This product is NOT commercially available in Canada at this time Aug 1993)


  1. McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
  2. Anon, "Cyclomydril(R)" package insert, Alcon, Laboratories Inc, Fort Worth, Texas, 1988.
  3. Isenberg S, Everett S, and Parelhoff E: A comparison of mydriatic eyedrops in low-weight infants, Ophthalmology 1984; 91: 278-279.

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