You can take Claritin and Benadryl together, but the effect of both drugs overlap, according to BJC HealthCare. Both Claritin and Benadryl are antihistamines, which means that taking them together would be duplicating the active drug of each medication.
Taking more of the same drug will not provide increased results. Therefore, taking Benadryl and Claritin at the same time will not improve the efficacy of either drug, according to BJC HealthCare. However, if an individual is interested in taking Benadryl in the evening to take advantage of the drowsiness it provides, taking the two together is not harmful. BHC HealthCare recommends taking Claritin in the morning and Benadryl in the evening.