<p>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 Brimonidine Tartrate can lead to an interference in intraocular pressure (IOP) lowering effect. No data are available on the level of circulating catecholamines after Brimonidine Tartrate is instilled. Caution, however, is advised in patients taking tricyclic antidepressants which can affect the metabolism and uptake of circulating amines. Although specific drug interaction studies have not been conducted with Brimonidine Tartrate, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anesthetics) should be considered.</p>