Blunted ocular hypotensive response by TCAs. Additive or potentiated effect w/ CNS depressants. Affected 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; isoprenaline, prazosin. Additive systemic effects w/ oral carbonic anhydrase inhibitors. Inhibited metabolism w/ CYP3A4 inhibitors.