Drug Interactions between brimonidine / dorzolamide / latanoprost / timolol ophthalmic and rizatriptan

MONITOR: Topically administered alpha-2 adrenergic receptor agonists such as apraclonidine and brimonidine are systemically absorbed, with the potential for producing rare but clinically significant systemic effects such as hypotension and bradycardia. The possibility for an additive or potentiating effect on blood pressure and heart rate should be considered when used with other medications that affect these parameters, such as ophthalmic and systemic beta blockers, vasodilators, cardiac glycosides, and antihypertensive agents.

MANAGEMENT: Blood pressure and pulse rate should be monitored regularly when topical alpha-2 adrenergic receptor agonists are prescribed in combination with cardiovascular drugs. Patients should be advised to notify their physician if they experience slow pulse, irregular heartbeat, dizziness, lightheadedness, or syncope.

Coadministration with rizatriptan may alter the plasma concentrations of drugs that are primarily metabolized by CYP450 2D6. Rizatriptan has been shown to be a competitive inhibitor of CYP450 2D6 in vitro, but only at high, clinically irrelevant concentrations and a clinically significant inhibitory effect on CYP450 2D6 has not been demonstrated in clinical drug interaction studies. Based on these observations, rizatriptan may be administered with CYP450 2D6 substrates without the need for increased clinical monitoring