Alphagan/Alphagan P 0.1% Drug Interactions

Although specific drug interaction studies have not been conducted with ALPHAGAN/ALPHAGAN P 0.1%, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives or anesthetics) should be considered.
Alpha-agonists, as a class (including ALPHAGAN 0.2%), may reduce pulse and blood pressure. Caution in using concomitant drugs such as beta-blockers (ophthalmic and systemic), anti-hypertensives and/or cardiac glycosides is advised.
Tricyclic antidepressants have been reported to blunt the hypotensive effect of systemic clonidine. It is not known whether the concurrent use of these agents with ALPHAGAN/ALPHAGAN P 0.1% in humans can lead to resulting interference with the IOP lowering effect. In experiments on rabbits, however, MAO inhibitors and tricyclic antidepressants did not alter the IOP response to brimonidine.
No data on the level of circulating catecholamines after ALPHAGAN/ALPHAGAN P 0.1% administration are available. Caution, however, is advised in patients taking tricyclic antidepressants which can affect the metabolism and uptake of circulating amines.