loratadine and Cardizem Interactions

Interactions between loratadine and Cardizem (diltiazem)

diltiazem and loratadine (Moderate Drug-Drug)

MONITOR: Coadministration with diltiazem may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism is decreased clearance due to inhibition of CYP450 3A4 activity by diltiazem.

MANAGEMENT: Caution is advised if diltiazem must be used concomitantly with medications that undergo metabolism by CYP450 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever diltiazem is added to or withdrawn from therapy.