mydriasis

Tropicamide (Ro 1-7683) is a synthetic muscarinic antagonist with anticholinergic properties similar to atropine. Upon ocular administration, it binds to and blocks muscarinic receptors in the sphincter and ciliary muscles, inhibiting cholinergic responses and causing pupil dilation and ciliary muscle paralysis. Tropicamide is used as a diagnostic agent to induce short-duration mydriasis and cycloplegia.

Yohimbine hydrochloride is a plant-derived alkaloid with alpha-2 adrenergic receptor blocking activity. By blocking presynaptic or postsynaptic alpha-2 adrenergic receptors, it promotes the release of norepinephrine and dopamine. It has been used in studies related to mydriasis and erectile dysfunction and is commonly used to induce hypertension models.

Dapiprazole, an alpha blocker, is used to reverse mydriasis after eye examination.

Methylatropine is an antagonist of muscarinic acetylcholine receptors (IC50= <0.1 nM in a radioligand binding assay using isolated porcine brain membranes) and a derivative of atropine .1,2It reduces acetylcholine-induced decreases in blood pressure in rats when administered intravenously with an ED50value of 5.5 μg/kg.2Methylatropine reduces salivation, induces mydriasis, and increases heart rate in dogs.3 1.Schmeller, T., Sporer, F., Sauerwein, M., et al.Binding of tropane alkaloids to nicotinic and muscarinic acetylcholine receptorsPharmazie50(7)493-495(1995) 2.Brezenoff, H.E., Xiao, Y.-F., and Vargas, H.A comparison of the central and peripheral antimuscarinic effects of atropine and methylatropine injected systemically and into the cerebral ventriclesLife Sci.42(8)905-911(1988) 3.Albanus, L.Central and peripheral effects of anticholinergic compoundsActa Pharmacol. Toxicol. (Copenh)28(4)305-326(1970)

Dapiprazole Hydrochloride (Glamidolo Hydrochloride) is an alpha-1-adrenergic antagonist that acts by blocking alpha-adrenergic receptors in the smooth muscle of blood vessels (arteries, arterioles and veins), gastrointestinal tract, and radial smooth muscle of the iris.

Moxisylyte, also known as thymoxamine, is a drug used in urology for the treatment of erectile dysfunction. It is an α1-adrenergic antagonist. Moxisylyte is also used for the short-term treatment of primary Reynaud's syndrome, a condition where the fingers and toes become discoloured in response to cold or emotional distress. Moxisylyte helps by improving blood circulation to the extremities. It is also used locally in the eye to reverse the mydriasis caused by phenylephrine and other sympathomimetic agents.