Can You Take Benadryl With Pepcid (Famotidine)?

Answer

There is no known drug interaction between Pepcid (famotidine) and Benadryl (diphenhydramine). They are considered safe to take together.

Although they both work on histamine receptors, they do so on different ones. Antihistamines like Benadryl block 'H1' receptors, while drugs like Pepcid, Zantac and Tagamet block 'H2' receptors, which which play a role in stomach acid secretion.

There is even some evidence that combining 'H1' and 'H2' blockers can be effective for treating itch not otherwise well-controlled with antihistamines alone.

About Benadryl (Diphenhydramine)

Benadryl is a first-generation antihistamine that is most commonly used to treat allergic reactions. It blocks the binding of histamine to H1 receptors. One of the most commonly seen side effects of this medication is sedation and drowsiness which is why Benadryl is commonly used as a sleep aid. A few of the other commonly seen side effects include:

• Constipation
• Urinary retention
• Blurred vision

Each dose of Benadryl lasts around 4 to 6 hours after taking by mouth.

About Pepcid (Famotidine)

Pepcid also blocks the binding of histamine, but it does so specifically in the stomach, at different receptors (H2), to lower the acidity of the stomach and help with symptoms of heartburn or acid reflux.

Because of the histamine blocking that this medication provides, it can also be used as an adjunctive treatment for patients who are experiencing allergic reactions. It is not as effective as Benadryl, but it can be used to help bolster the response.