Yes, it is safe. there is no known drug interaction between the 2 medicines
Penicillin V is an antibiotic in the penicillin group of drugs. It fights bacteria in your body. While Benadryl is an antihistamine. Benadryl is used to treat sneezing; runny nose; itching, watery eyes; hives; rashes; itching; and other symptoms of allergies and the common cold.