<p>There are no reports of potentially hazardous interactions with other drugs. In contrast to many other histamine H1 receptor antagonists, Loratadine has no potentiating effects when administered concurrently with alcohol, as measured by psychomotor performance studies. Concomitant therapy with drugs that inhibit or are metabolized by hepatic cytochromes P450 3A4 and 2D6 may elevate plasma concentrations of either drug and this mayifesult in adverse effects. Cimetidine inhibits both enzymes while erythromycin or ketoconazole inhibits P450 3A4. These drugs increase loratadine serum concentrations but no adverse effects are reported.</p>