I took 10 mg loratadine (non drowsy 24 hr claritin) 8 hours ago for my allergies. it didnt work and im trying to go to bed so i was wondering if it was safe to take 25 mg diphenhydramine hcl (benadryl) since it does make you drowsy?

Likely safe: Interaction: Diphenhydramine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. It is considered Minor with Significance Unknown. Best regards for good health.

Expected pattern: Loratadine is one of several non-drowsy antihistamines that take up to a day to achieve a blood level in your system to reach peak effect. Daily use maintains that level. Diphenhydramine works differently achieving peak effect in an hour or so but leaving the body sooner. I see no reason not to use both as their side effect profile does not overlap.The drowsiness would be the same clinically.