Drug Interactions Beta-Adrenergic Blocking Agents Patients who are receiving a beta-adrenergic blocking agent orally and Timolol maleate ophthalmic gel forming solution should be observed for potential additive effects of beta-blockade, both systemic and on intraocular pressure. Calcium Antagonists Caution should be used in the coadministration of beta-adrenergic blocking agents, such as Timolol maleate ophthalmic gel forming solution, and oral or intravenous calcium antagonists because of possible atrioventricular conduction disturbances, left ventricular failure, or hypotension. quinidine, SSRIs) and timolol.
Source: FDA drug label - timolol maleate ophthalmic gel forming solution 0.25%