Mydriasis w/ adrenaline. Potential for additive effects resulting in hypotension &/or marked bradycardia w/ oral Ca channel blockers, β-adrenergic blocking agents, antiarrhythmics (including amiodarone), digitalis glycosides, parasympathomimetics, guanethidine, catecholamine-depleting drugs (eg, reserpine). Possible AV conduction disturbances, left ventricular failure, & hypotension w/ oral or IV Ca antagonists. Simultaneous use of β-adrenergic blocking agents & digitalis w/ diltiazem or verapamil may have an additive effect in prolonging AV conduction time. Potentiated systemic β-blockade w/ CYP2D6 inhibitors (eg, quinidine, fluoxetine, paroxetine). Enhanced rebound effect of HTN when stopping administration of clonidine. Blocked systemic effects of β-agonists (eg, adrenaline). Increased hypoglycaemic effect of insulin or oral antidiabetics. Monitor IOP when using w/ systemic or topical steroids. Use w/ caution when co-administered w/ psychotropic adrenergics.