Is zantac (ranitidine) used for allergies?

Not exactly: Zantac (ranitidine) is an h2 (histamine) blocker that is typically used for ge (acid) reflux. However, it is commonly used to treat chronic hives in combination with traditional antihistamines. It is also used for additional treatment of severe (anaphylaxis) allergic reactions although first line treatment is Epinephrine and h1 antihistamine. It will not help allergic rhinitis.