No interaction studies have been performed.
Interactions have been reported with systemic administration of the individual components. Concomitant use of topical steroids and topical NSAIDs may increase the potential for corneal healing Nevertheless, systemic absorption of ophthalmic tobramycin and dexamethasone is low and the chance of any interaction is minimal.
When using pupil-dilating eye drops (atropine and other anticholinergic substances), which may cause elevation of intraocular pressure, concomitant use of TOBRADEX may lead to an additional elevation of intraocular pressure.
In patients treated with ritonavir or other strong CYP3A4 inhibitors, plasma concentrations of dexamethasone may be increased (see Precautions).
CYP3A4 inhibitors (including ritonavir and cobicistat): may decrease dexamethasone clearance resulting in increased effects and adrenal suppression/Cushing's syndrome. The combination should be avoided unless the benefit outweighs the increased risk of systemic corticosteroid side-effects, in which case patients should be monitored for systemic corticosteroid effects.
If more than one eye preparation is being used, the products must be administered at least 5 minutes apart. Eye ointments should be administered last.