Drug Interaction Report

MONITOR: Topically administered alpha-2 adrenergic receptor agonists such as brimonidine are systemically absorbed, with the potential for producing rare but clinically significant systemic effects. Despite relative alpha-2 selectivity, theoretical concerns exist that coadministration with monoamine oxidase inhibitors (MAOIs) may increase the risk of hypertension due to potentiation of alpha-1 stimulation, which produces vasoconstriction. MAOIs may also theoretically interfere with the metabolism of brimonidine, which may result in increased systemic adverse effects such as drowsiness, dizziness, lightheadedness, hypotension, and bradycardia. However, an interaction with MAOIs has not been reported in the medical literature.

MANAGEMENT: Patients receiving brimonidine in combination with MAOIs should be made aware of the potential for increased adverse effects, and counseled to avoid activities requiring mental alertness until they know how these agents affect them. Patients should also avoid rising abruptly from a sitting or recumbent position and notify their physician if they experience orthostasis or tachycardia. Blood pressure should be monitored closely.