Apraclonidine is an alpha2-adrenoreceptor agonist and reduces intraocular pressure. It is used to control increases in intra-ocular pressure associated with ocular surgery. It is sometimes also used in the pre-operative period - short-term use only. Apraclonidine 0.5% is used as short-term adjunctive treatment of chronic glaucoma not adequately controlled with other drugs.
Brimonidine is a selective alpha2-adrenoreceptor stimulant. It may cause allergic conjunctivitis. It should not be used with tricyclic antidepressants or MAOIs. It can be an alternative where beta-blockers cannot be used; it can also be used in addition to a beta-blocker.