Final answer:
Diphenhydramine, commonly known as Benadryl, is used to treat allergic reactions by blocking histamine activity. Antihistamines like Benadryl are not used to treat hypertension, hyperthyroidism, or diabetes.
Step-by-step explanation:
Diphenhydramine, sold under the brand name Benadryl among others, is an antihistamine medication primarily used to treat allergic reactions. It works by blocking the effects of histamine, a substance in the body that causes allergic symptoms like itching, sneezing, and runny nose. Mild allergy symptoms such as watery, itchy eyes, swollen tissues, and sneezing are commonly treated with antihistamines.Antihistamines are also effective in preventing mast cells from releasing histamines and causing uncomfortable allergy symptoms. In more severe cases, such as anaphylaxis, which is a life-threatening allergic reaction, an epinephrine injection is used as an initial treatment to counteract the massive release of histamines.Thus, referring to the question, diphenhydramine such as Benadryl can be given to treat b) Allergic reactions. It is not used to treat hypertension, hyperthyroidism, or diabetes.