6 hrs ago had Allergic reaction to bee sting, emt gave Benadryl, (diphenhydramine) then doctors at hospital gave prednisone and pepcid, Can next dose benadryl (diphenhydramine) b taken?

Yes. If you feel you still need it, but don't exceed recommended daily dose for diphenhydramine from all sources (300 mg /day), depends on the reaction too was it a local or whole body reaction? keep taking the benadryl for the next 24 -48 hours every 4-6 hours as needed 25- 50 mg , don't drive, and take the medicines prescribed at ER, if it was a whole body reaction, see an allergist, take care .
Yes. BUT note that pepcid is just another old wive's tale. EMT people believe it helps certain allergic reactions. THEY ARE WRONG. No harm but no help. Benadryl (diphenhydramine) is a poor choice for histamine reactions. It is mostly used as a sleeping pill. Amazing that EMT people have not learned this. Far more effective, far safer, is CETIRIZINE [Zyrtec]. Official dose is 1 pill [10mg] but some people need 3 or 4.