Freddie asked
Is Zantac an antihistamine? I am getting conflicting information.
Answer
Zantac (ranitidine) is technically classified an antihistamine, but works on different receptors than the more well known antihistamines such as Claritin, Zyrtec and Benadryl.
How Does Zantac Work?
Zantac specifically blocks histamine at the H2 receptors while the antihistamines used for allergies block histamine at the H1 receptor.
H2 blocking antihistamines are indicated for the treatment of many conditions resulting from increased acid production in the stomach including:
- Ulcers
- Dyspepsia
- Gastroesophageal reflux disease (GERD)
- Esophagitis
H2 blockers, like Zantac, work to reduce acid production by blocking parietal cells from being stimulated to produce acid by histamine. Histamine is not the only substance that stimulates acid production in parietal cells however so not all acid production is stopped.
H2 Blocker Information
Although H2 blockers are most commonly used for issues related to the stomach, they do appear to be helpful for certain allergic reactions. In fact, many H2 blockers, such as Zantac are also used off label for some allergic reaction related symptoms due to their histamine blocking capabilities.
In addition, evidence suggests adding a H2 blocker to a H1 blocker works better for treating hives and itching than a H1 blocker alone.
The most common H2 blockers that are available by both prescription and over the counter (OTC) are:
- Zantac (ranitadine)
- Pepcid (famotidine)
- Tagamet (cimetidine)
Summary
- Zantac (ranitidine) is classified as a H2 blocker, meaning that is blocks H2 receptors.
- Although classified as an antihistamine, Zantac is does not affect H1 receptors, like Benadryl or Claritin.
- H2 blockers are most effective for the treatment of stomach related problems like heartburn and ulcer prophylaxis.
- H2 blockers can sometimes be beneficial for the treatment of hives and itching.
