MAOIs. TCAs may blunt the ocular hypotensive response. Additive or potentiating effect w/ CNS depressants eg, alcohol, barbiturates, opiates, sedatives or anaesth. Drugs affecting metabolism & uptake of circulating amines eg, chlorpromazine, methylphenidate, reserpine, serotonin-norepinephrine reuptake inhibitors. Reduced pulse & BP w/ α-adrenergic agonists. Concomitant use w/ antihypertensives &/or cardiac glycosides; agonists or antagonists of the adrenergic receptor eg, isoprenaline, prazosin. Additive systemic effects w/ oral carbonic anhydrase inhibitors. Inhibited metabolism w/ CYP3A4 inhibitors eg, ketoconazole, itraconazole, clotrimazole, ritonavir & troleandomycin.