Antihistamine and Diphenhydramine

Antihistamine noun - A medicine used to treat allergies and hypersensitive reactions and colds; works by counteracting the effects of histamine on a receptor site.

Diphenhydramine and antihistamine are semantically related. In some cases you can replace term "Diphenhydramine" with "Antihistamine", this nouns are similar.

Diphenhydramine noun - Antihistamine (trade name Benadryl) used to treat allergic reactions involving the nasal passages (hay fever) and also to treat motion sickness.

Antihistamine and diphenhydramine are semantically related. You can use "Antihistamine" instead a noun "Diphenhydramine".