Benadryl (diphenhydramine) is a brand-name drug that treats symptoms of conditions, including allergies and colds. Benadryl has interactions with alcohol and certain health conditions. Examples include breathing problems, glaucoma, and enlarged prostate.

An interaction occurs when one substance causes another substance to have a different effect than expected.

Benadryl comes in different forms, and they have similar interactions. The forms are:

  • oral forms:
    • liquid-filled capsule
    • tablet
    • children’s chewable tablet
    • children’s solution
  • topical forms:
    • cream
    • gel
    • solution
    • spray

To learn more about Benadryl’s interactions, keep reading. For additional information about Benadryl, including details about its uses, see this article.

The manufacturer of Benadryl recommends avoiding alcohol while taking the drug. This is because sleepiness is a side effect of Benadryl, and consuming alcohol can worsen it. Excessive sleepiness could be dangerous while driving or performing other tasks that require you to be alert.

Alcohol can also worsen other side effects of Benadryl. Examples include confusion, dizziness, and headache.

If you drink alcohol, talk with your doctor or pharmacist before taking Benadryl. They can help determine whether you may be able to take a drug other than Benadryl for your condition.

The manufacturer of Benadryl has not reported any interactions with other medications. However, it’s possible that new interactions may be recognized in the future. For example, new drugs could be approved that interact with Benadryl.

Before you start treatment with Benadryl, tell your doctor and pharmacist which prescription, over-the-counter, and other medications you take. By sharing this information with them, you may help prevent possible interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Benadryl may have other interactions, such as with supplements, foods, vaccines, or even lab tests. You’ll find details below.

Benadryl interactions with supplements

It’s possible for drugs to interact with supplements such as vitamins and herbs.

Benadryl interactions with herbs

There were no specific reports of herbs interacting with Benadryl. However, it’s still important to check with your doctor or pharmacist before taking any of these products during Benadryl treatment.

Benadryl interactions with vitamins

Vitamins have not been reported to interact with Benadryl. Keep in mind that you should still talk with your doctor or pharmacist before taking any vitamins during your Benadryl treatment.

Benadryl interactions with food

No food interactions with Benadryl have been reported. If you’d like to learn more about eating certain foods while you take Benadryl, talk with your doctor.

Benadryl interactions with vaccines

There were no reports of vaccines interacting with Benadryl. Your doctor can tell you more about vaccines and Benadryl.

Benadryl interactions with lab tests

Lab tests have not been reported to interact with Benadryl. If you’d like additional information about having lab tests while taking Benadryl, talk with your doctor.

Benadryl and cannabis or CBD

Cannabis (marijuana) and cannabis products, such as cannabidiol (CBD), have not been specifically reported to interact with Benadryl. However, as with any drug or supplement, talk with your doctor before taking cannabis in combination with Benadryl. The impact of cannabis may affect how well you stick to your Benadryl treatment plan.

Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.

Certain medical conditions and other factors may increase the risk of interactions with Benadryl. Before you take Benadryl, be sure to talk with your doctor about your health history. Benadryl may not be the right treatment option for you if you have certain medical conditions or other factors affecting your health.

Health conditions or factors that might interact with Benadryl include:

  • Breathing problems. Before taking Benadryl, tell your doctor if you have breathing problems such as emphysema or chronic bronchitis. Benadryl may worsen these conditions. Your doctor can advise you on whether Benadryl is safe for you to take.
  • Glaucoma. If you have glaucoma, talk with your doctor before starting Benadryl treatment. The drug may worsen this condition. Your doctor can advise you on whether Benadryl is right for you.
  • Enlarged prostate. If you have an enlarged prostate, you should talk with your doctor before taking Benadryl. It’s especially important to tell them if the condition causes you trouble with urinating. Benadryl may make it more difficult than usual for you to urinate. Your doctor can tell you whether the medication is a safe treatment option for you.
  • Low sodium diet. Before taking Benadryl, tell your doctor if you’re following a low sodium diet. The drug may cause you to produce less urine or urinate less often than usual. This decreased urination could lower your sodium levels even further. Your doctor can advise you on whether Benadryl is safe for you.
  • Pregnancy. It’s likely safe to take Benadryl while pregnant. To make sure, talk with your doctor or pharmacist before taking the drug during pregnancy. They’ll discuss any safety issues with taking Benadryl while pregnant.
  • Breastfeeding. Benadryl may pass into breast milk. In a child who is breastfed, this could cause side effects such as drowsiness or extreme crying. These side effects usually occur with larger doses or repeated exposure to Benadryl. If you’re interested in taking the medication while breastfeeding, first talk with your doctor or pharmacist. They may recommend a different treatment option for your condition.
  • Allergic reaction. If you’ve had an allergic reaction to Benadryl or any of its ingredients, your doctor will likely recommend not taking Benadryl. Ask them about other treatments that may be better choices for you.

Here are some frequently asked questions about Benadryl and possible interactions.

Does Benadryl interact with other antihistamines such as Claritin, hydroxyzine, or Zyrtec?

Benadryl is not known to interact with Claritin (loratadine), Vistaril (hydroxyzine), or Zyrtec (cetirizine). However, taking Benadryl in combination with any of these drugs is not typically advised, unless your doctor recommends it. This is because Benadryl and these medications all belong to a class of drugs called antihistamines. Taking more than one antihistamine at a time could worsen the side effects of this drug class. Examples of these side effects include dry mouth, headache, and sleepiness.

To learn more about possible side effects of Benadryl, see this article. If you’d like to find out how Benadryl compares with Claritin and Zyrtec, see this article. You can also talk with your doctor and pharmacist.

Are there interactions between Benadryl and sleep aids such as melatonin, L-theanine, or trazodone?

No, Benadryl is not known to interact with melatonin, L-theanine, or trazodone. Melatonin and L-theanine are herbal supplements used to help with sleep. Trazodone is a type of antidepressant that’s sometimes prescribed for insomnia.

Sleepiness is a very common side effect of Benadryl. Taking Benadryl with melatonin, L-theanine, or trazodone could cause excessive sleepiness. For this reason, taking Benadryl with any of these products is not typically advised.

If you’re taking melatonin, L-theanine, or trazodone, talk with your doctor or pharmacist before taking Benadryl. They can recommend whether the combination of products is safe.

Is Benadryl known to interact with blood pressure medications?

There’s no known interaction between Benadryl and blood pressure medications.

However, if you take blood pressure medication, you’re encouraged to talk with your doctor before taking Benadryl. It’s possible for Benadryl to cause low blood pressure. Taking Benadryl with blood pressure medication could cause your blood pressure to decrease to a level that’s too low.

It’s also important to note that Benadryl is available in combination cold products that can increase blood pressure. These combination products may contain decongestants such as phenylephrine. Keep in mind that Benadryl itself is not known to increase blood pressure.

To learn more about taking Benadryl and blood pressure medication, talk with your doctor or pharmacist.

Do Tylenol or Advil interact with Benadryl?

Benadryl is not known to interact with Tylenol (acetaminophen) or Advil (ibuprofen).

In fact, Benadryl is often available in combination products that contain Tylenol or Advil. These products are used to treat symptoms of allergies and colds. Examples of these symptoms include body aches, sneezing, and a runny nose.

If you’re interested in taking Benadryl with Tylenol or Advil, first talk with your doctor or pharmacist. They can advise you on whether these medications are right for relieving your symptoms.

Is there an interaction between Benadryl and Flonase?

Benadryl does not interact with Flonase (fluticasone).

Flonase is an over-the-counter nasal spray used to treat allergy symptoms, such as a runny nose. Benadryl is often used in combination with Flonase to ease allergy symptoms.

If you’d like to take Benadryl with Flonase, talk with your doctor or pharmacist. They can instruct you on how to take these medications together safely.

You can take certain steps to help prevent interactions with Benadryl. Your doctor and pharmacist are key resources, so reach out to them before starting treatment. For example, you should plan the following:

  • Let them know if you drink alcohol or take cannabis.
  • Tell them about any other medications you take, as well as any supplements, herbs, and vitamins.
  • Create a medication list, which your doctor and pharmacist can help you fill out.

It’s also important to read the packaging of Benadryl and other paperwork that comes with the drug. The paperwork, sometimes called the drug facts label, may contain details about interactions. If this information is difficult to understand, ask your doctor or pharmacist to help explain it.

You can also help prevent interactions with Benadryl by taking it exactly as your doctor recommends.

Besides learning about interactions, you may want to find out more about Benadryl. These resources might help:

  • Overview of Benadryl. For a general overview of Benadryl, you can refer to this article.
  • Side effects. If you’re interested in learning about the side effects of Benadryl, see this article.
  • Drug comparison. For information abouthow Benadryl compares with Claritin, Zyrtec, Allegra, Unisom, and melatonin, see this article.
  • Facts about the conditions Benadryl treats. You can learn more about allergies in our asthma and allergies hub and from this list of allergy articles.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.