Tropicamide

Tropicamide (troe-PIK-a-mide) is a muscarinic acetylcholine receptor blocker. It is used to dilate (enlarge) the pupil of the eye in order to allow better examination of the lens, vitreous humor, and retina. Due to its relatively short duration of effect (4 - 8 hours), it is typically used during eye examinations, but may also be used before or after eye surgery.

Application of tropicamide produces short acting mydriasis (dilation) and cycloplegia. Systemic side effects are very rare, although loss of consciousness has been reported in a ten-year-old child after administration of tropicamide eyedrops.

Tropicamide, a parasympatholytic, is occasionally administered in eye drops in combination with p-hydroxyamphetamine (brand name Paremyd&reg;), which is a sympathomimetic. The use of drugs stimulating multiple divisions of the autonomic nervous system ensures the dilation the pupil without opposing muscle group firing.

Other brand names include Mydriacyl.