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

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: Coadministration of alectinib with other agents that can slow the heart rate may increase the risk of bradycardia. In clinical trials, 7.5% of patients developed bradycardia during treatment with alectinib. Twenty percent of 221 patients for whom serial electrocardiograms were available had heart rates of less than 50 beats per minute (bpm).

MANAGEMENT: Caution is advised when alectinib is prescribed with other drugs that can cause bradycardia (e.g., beta-blockers; calcium channel blockers; digitalis; dolasetron; flecainide; ivabradine; lacosamide; mefloquine; moricizine; propafenone; quinine; succinylcholine; sunitinib; thalidomide; anticholinesterase or cholinergic agents; protease inhibitors such as atazanavir, lopinavir/ritonavir, and saquinavir/ritonavir). Heart rate and blood pressure should be monitored regularly, and patients should be counseled to seek medical attention if they experience dizziness, lightheadedness, fainting, or irregular heartbeat. Dosage modification of alectinib is not required in cases of asymptomatic bradycardia. However, if symptomatic bradycardia occurs, the manufacturer recommends withholding alectinib until recovery to asymptomatic bradycardia or to a heart rate of >=60 bpm. Evaluate concomitant medications known to cause bradycardia and all antihypertensive medications, then consider dosage adjustments or discontinuation of concomitant medication(s) or alectinib in accordance with the product labeling.