Intramol Drug Interactions

Although Timolol ophthalmic solution has little or no effect on pupil size, mydriasis has occasionally been reported when Timolol is given with adrenaline. The effects of intraocular pressure or the known effects of systemic beta-blockade such as hypotension or bradycardia may be exaggerated when Timolol ophthalmic solution is given to patients already receiving an oral beta-blocking agent. The response of these patients should be closely monitored.
As Timolol ophthalmic solution may be absorbed systemically, the following interactions seen with oral beta-blockers may occur: Calcium channel blockers (verapamil and diltiazem): Negative effect on contractility and atrio-ventricular conduction can lead to cardiac failure and hypotension.
Digitalis glycosides: In association with calcium channel blockers may increase atrio-ventricular conduction time.
Catecholamine-depleting drugs (rauwolfia, alkaloids, reserpine, etc.): Potentiation of hypotension and/or marked bradycardia.
Clonidine: Increased risk of "rebound hypertension" on discontinuation of clonidine.
Class I antiarrhythmic drugs (e.g., disopyramide, quinidine, and amiodarone): Potentiation of bradycardia, sinus arrest and AV block.
Anaesthetic drugs: Increased risk of myocardial depression and hypotension due to blockade of cardiac response to reflex sympathetic stimuli.
Cimetidine, hydralazine, phenothiazines, and alcohol: May cause increase plasma level of Timolol.