Substances that act as inhibitors of the CYP3A4 enzyme such as ketoconazole, erythromycin, cimetidine, and furanocoumarin derivatives (found in grapefruit) lead to increased plasma levels of<unk>  — that is, more of the drug was present in the bloodstream than typical for a dose. This had clinically significant effects in controlled trials of 10 mg<unk>  treatment Antihistamines should be discontinued 48 hours prior to skin allergy tests, since these drugs may prevent or diminish otherwise-positive reactions to dermal activity indicators.
Loratadine
Desloratadine
Rupatadine
Olopatadine
Roxadustat
Terfenadine
Mibolerone
Ecallantide