Drug Criteria & Outcomes: Loratadine (Claritin) vs. desloratadine (Clarinex) formulary interchange

By Sharon W. Cooper, PharmD candidate
Harrison School of Pharmacy, Auburn (AL) University

Desloratadine (Clarinex), a major metabolite of loratadine (Claritin), is the newest medication indicated for the treatment of allergic rhinitis. It is often a misconception that new drugs are more beneficial than their predecessors. (See the comparison chart to clarify the similarities between these two antihistamines.)

The safety and efficacy of desloratadine is virtually identical to that of loratadine, the current formulary agent. Although desloratadine is currently less expensive than loratadine, the patent on loratadine expired in December 2002. Therefore, a less expensive, equally effective generic will be available soon. This will likely decrease loratadine’s price by 50% or more. It is recommended that loratadine continue as the formulary representative for this drug class. Desloratadine should be interchanged automatically to loratadine as follows: Clarinex 5 mg QD and Clarinex Reditabs 5 mg QD interchanged to Claritin 10 mg QD.