Which drug is commonly used for short-term pupil dilation?

Tropicamide is commonly used for short-term pupil dilation due to its rapid onset and short duration of action, making it particularly suitable for ophthalmic examinations and procedures. When applied topically to the eye, tropicamide works by blocking the action of acetylcholine on the sphincter muscle of the iris, leading to dilation of the pupil (mydriasis) and paralysis of the ciliary muscle (cycloplegia). This allows for better visualization of the internal structures of the eye during diagnostic procedures.

Other drugs mentioned, like atropine, are effective for pupil dilation but have a much longer duration of action, making them less ideal for short-term use. Phenylephrine can also cause pupil dilation but is primarily a sympathomimetic agent with different uses in ocular conditions, while brimonidine is mainly utilized for lowering intraocular pressure and does not serve as a primary agent for inducing mydriasis. Thus, tropicamide’s specific characteristics align perfectly with the need for short-term pupil dilation.