I have bad seasonal allergies, zyrtec and clartin arent working. can i take benadryl (diphenhydramine) with the zyrtec?

OTC allergy meds: Combining Benadryl (diphenhydramine) and zyrtec may make you very drowsy so take it at night. You may like to try fexofenadine or Allegra instead; it's also non-sedating and can be taken once a day. Zyrtec and Claritin have derivatives that can be obtained only by prescription from your doctor. There are also nasal sprays that your doctor may try on you.