The effect of the prescription to over-the-counter switch of Claritin on the use of alternative prescription allergy medications: The role of prescription drug benefit design and brand loyalty

Health insurers expected cost savings from the prescription (Rx)-to-OTC switch of ClaritinRTM, the most popular non-sedating antihistamine (NSA) drug, through reduced utilization of prescription NSAs. However, the insured's allergy drug utilization behavior may be influenced by the existence of Claritin'sRTM prescription-status alternatives and the cost sharing amounts for these allergy medications. The purpose of this study was to examine the effect of Claritin'sRTM Rx-to-OTC switch on the utilization of alternative prescription allergy medications focusing on the role of individuals' out-of-pocket cost amount and brand loyalty.; A retrospective longitudinal design was employed using pharmacy claims data obtained from the Wellmark Blue Cross Blue Shield of Iowa. Individuals who were continuously enrolled in employer-based pharmacy plans and who took more than one ClaritinRTM prescription during the year prior to OTC switch of ClaritinRTM were selected for the study population (N=13,947). The utilization change was measured by the number of prescriptions. A binomial logit model was used to examine the effects of the insured's cost-sharing amount and brand loyalty on the alternative prescription drug substitution behavior. Brand loyalty was measured based on the frequency of individuals' previous substitution behavior for allergy medications. Multinomial logit models were constructed to investigate the effects of individuals' out-of-pocket cost difference for allergy drugs on the choice among five allergy drug classes: (1) no Rx drug use; (2) Rx NSA; (3) nasal steroids; (4) Singulair RTM; and (5) sedating antihistamines.; The average number of prescriptions for alternative Rx non-sedating antihistamine drugs and for all Rx allergy drugs excluding ClaritinRTM increased after the Rx-to-OTC switch of ClaritinRTM. As the cost-sharing amount for Pre-Period ClaritinRTM increased and as brand loyalty increased, individuals were more likely not to substitute an alternative prescription drug for ClaritinRTM. As the out-of-pocket cost difference increased, all of four prescription alternatives were less likely to be chosen compared to no Rx drug use. The pharmacy benefit plan structures of coinsurance and deductible were also significantly related to a lower likelihood of alternative prescription drug substitution.; This study shows the importance of pharmacy benefit plan design in understanding the effect of an Rx-to-OTC switch.