Can i take hydrocodone with benadryl (diphenhydramine)?

Yes but makes drowsy: Hydrocodone is a pain medication that will cause drowsiness. Benadryl (diphenhydramine) is an anti-histimine which also causes drowsiness and sometimes will help boost the pain controlling effect of the hydrocodone, thus potentially reducing the dose that you need. So yes they could be taken together cautiously, but be careful of the combined drowsiness.

Yes: But both are sedating, so start with a low dose. Discuss it with your doctor.

Cautiously: Both are respiratory and mental depressants and therefore should be taken with caution.