Image: 4 panels organized in a rectangle following a sequential order like a comic strip. The first panel is of a man with a very serious face stating, “Hey man, got any diphenhydramine?” The second panel is a grainy picture of the actor Tony Stark with a slightly inquisitive face and saying, “What’s that?” The third panel is an identical copy of the first image and saying, “Benadryl the allergy medicine.” The fourth and final panel is a grainy picture of Tony Stark rolling his eyes and taking a deep breath.
Antihystamine is very specific. Antihistamine is quite generic and it depends on whether you want to treat allergies or schizophrenia. Here is a list from Wikipedia of the most common type of antihistamines (targeting the H¹ receptor)
List of H1 antagonists/inverse agonists