- Glaucoma. Apraclonidine is used for pre&postlaser prophylaxis of intraocular pressure spikes.
- To reduce the penetration of clonidine into the brain, a polar (hydrophilic)
- analog, apraclonidine, was developed for ophthalmic use. As a single
- drop, apraclonidine is a very effective ocular hypotensive agent. Maximal
- pressure reduction in the treated eye was 37% (6.5 mmHg) and lasted up
- to 12 hours. The dose-response curve for apraclonidine plateaus between
- 0.25% and 0.5%. Most of the unwanted effects of apraclonidine are local
- and are related to α1-adrenoceptor stimulation. These include conjunctival
- blanching, eyelid retraction, and mild mydriasis. Apraclonidine has a very
- low potential for systemic effects.
- Approved for use in the United States in 1996, brimonidine is similar to
- clonidine in its relative α2-adrenoceptor agonism, lipophilicity, and relative
- lack of α1-adrenoceptor agonism. Brimonidine achieves better penetration
- of the cornea than apraclonidine, although it has a theoretical potential for
- greater untoward effects such as sedation and systemic hypotension.
- Decreased production and increased outflow of aqueous humor.
- α2-adrenoceptor agonists and β-adrenoceptor antagonists reduce aqueous humor flow by reducing aqueous humor production. In contrast to apraclonidine, brimonidine also increases uveoscleral outflow as measured by fluorophotometry.
- The most frequent adverse events associated with brimonidine are oral
- dryness, ocular hyperemia, ocular discomfort, headache, and fatigue.
- Less frequent effects include corneal staining and photophobia. Rare
- events included lid crusting, abnormal taste, and depression.