Can you give a 8 month old zyrtec and benadryl (diphenhydramine) in the same day?

Yes, but...: That's a lot of medicine for an 8 month old. Make sure it has been ok'd by your pediatrician, and this is not a good long term combination. If that little one has that severe of allergies, might consider adding a med like singulair (montelukast) to get allergies under control. Also, try to reduce exposure to the allergens rather than adding more medicine.

Allergy testing : Determining the type and degree of allergic responses is an important part of your child’s management. Avoid common allergens such as dust,mold,pet dander and the Benadryl may be used for a hives reaction or acute symptoms of an allergic reaction.The Zyrtec is longer acting, and both should be used after consultation with your pediatrician.