Taking Rolaids With Benadryl

In our latest question and answer, the pharmacist discusses whether or not you can take Rolaids and Benadryl at the same time.

May 14, 2018

Jennifer asked

Can you take Benadryl and Rolaids together?

At a glance

  • There is no known interaction between Rolaids (an antacid) and Benadryl.


Rolaids and Benadryl do not have a known drug interaction and can safely be taken together.[1]


Benadryl doesn’t interact with Rolaids because it doesn’t bind to calcium or magnesium and it doesn’t require acid to be fully absorbed. It is safe to take Benadryl and Rolaids together and both medications will be effective.

Even though Benadryl doesn't interact with Rolaids, always be sure to ask your pharmacist or doctor about any other medications you are taking since antacids do interact with many drugs (notably thyroid medications).

What Are Rolaids?

Rolaids are a commonly used antacid product that is available over-the-counter. They are available as chewable tablets or soft chews and are used to treat heartburn and indigestion. Rolaids contain two active ingredients:[2]

  • Calcium carbonate
  • Magnesium hydroxide

Both of these ingredients work by neutralizing the acid in the stomach. At the first sign of heartburn or indigestion, 2 to 4 tablets can be taken up to four times a day. No more than 8 tablets should be taken in 24 hours and if you know you have high calcium or magnesium levels, you should not use Rolaids without talking to your doctor first.

Rolaids can interact with many drugs in two different ways. There are medications that require acid to be absorbed and work fully, so Rolaids can decrease the amount of acid in the stomach and stop these kinds of drugs from working. Also, the calcium and magnesium in the Rolaids can bind to other drugs and stop them from being absorbed. It is always a good idea to look into interactions with Rolaids if you take prescription drugs.

What Is Benadryl?

Benadryl is an antihistamine used to treat allergy symptoms. It is classified as a first-generation antihistamine and causes considerable drowsiness in most individuals. Each dose will begin working in 30 to 60 minutes and should last around 4 to 6 hours.[3]

  1. ^ Elsevier ClinicalKey: Diphenhydramine Monograph. ClinicalKey
  2. ^ Elsevier ClinicalKey: Rolaids Monograph. ClinicalKey
  3. ^ Antihistamines and allergy. PubMed

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