Drug Interaction Report

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.

MONITOR: Beta-adrenergic blockers (including ophthalmic formulations) may increase the severity and duration of acute anaphylactic reactions to antivenins. In addition, anaphylaxis may be resistant to the usual treatment modalities. The mechanism is unknown.

MANAGEMENT: Patients should be closely monitored for signs of severe, acute hypersensitivity reactions during administration of antivenins, and facilities and equipment for resuscitation, cardiovascular support, and airway management should be immediately available. Clinicians should be aware that larger doses of epinephrine or other adrenergic agents may be required.