Amongst the following antihistamines, which are antacids?
(a) Ranitidine
(b) Brompheniramine
(c) Terfenadine
(d) Cimetidine

Answers: (a) and (d).

Histamine is a substance that stimulates the secretion of pepsin and hydrochloric acid. There are some antacids like cimetidine were designed to prevent the interaction of histamine with the receptors present in the stomach wall. As a result, less HCl is released and the cause of hyperacidity is controlled/cured.
Ranitidine and cimetidine are antihistamines which are used as antacids. These drug result in the release of a lesser amount of acid. It is used to cure hyperacidity.

Brompheniramine is an antihistamine. It is used to treat a runny nose, sneezing, itching and watery eyes caused by the allergy.
Terfenadine, an antihistamine, was used for allergy.