They can be safely taken together but you should speak to your local pharmacist or your doctors nurse before mixing them
Diphenhydramine (Benadryl) Fexofenadine (Allegra) Loratadine (Claritin) Antihistamines can ease your symptoms, but they work best when you take them before you feel a reaction
The main difference between first-generation and second-generation
Diphenhydramine – the proarrhythmic effect, due to the influence on potassium channels, was reported while administering medically overdosed