is weed an antihistamine

Drug Interactions between Benadryl and cannabis

This report displays the potential drug interactions for the following 2 drugs:

  • Benadryl (diphenhydramine)
  • cannabis

Interactions between your drugs


cannabis (Schedule I substance)

Applies to: Benadryl (diphenhydramine) and cannabis

Using diphenhydrAMINE together with cannabis (Schedule I substance) may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating. Some people, especially the elderly, may also experience impairment in thinking, judgment, and motor coordination. You should avoid or limit the use of alcohol while being treated with these medications. Also avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medications affect you. Talk to your doctor if you have any questions or concerns. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Drug and food interactions

cannabis (Schedule I substance)

Applies to: cannabis

Alcohol can increase the nervous system side effects of cannabis (Schedule I substance) such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with cannabis (Schedule I substance). Do not use more than the recommended dose of cannabis (Schedule I substance), and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

See Also

  • Benadryl Drug Interactions
  • Benadryl General Consumer Information
  • Cannabis Drug Interactions
  • Drug Interactions Checker
Drug Interaction Classification
These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.

Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some mixtures of medications can lead to serious and even fatal consequences.

A Moderate Drug Interaction exists between Benadryl and cannabis. View detailed information regarding this drug interaction.

Weed Allergy Symptoms and Treatment

Angela Morrow, RN, BSN, CHPN, is a certified hospice and palliative care nurse.

Daniel More, MD, is a board-certified allergist and clinical immunologist with a background in internal medicine.

Could you have a marijuana allergy? Is it possible to be allergic to weed or pot? Whether you are new to medicinal marijuana (or legal marijuana) or have used it in the past without a problem, it is quite possible to have a marijuana allergy.

Let’s take a look at the symptoms of a weed allergy, allergy to edibles, the problems associated with diagnosing the allergy, and what you can do if you have one.


A marijuana allergy can cause skin problems if the plant or its flowers are handled. Symptoms of skin irritation might include:

  • Itching
  • Redness
  • Rash or hives
  • Dry, scaly skin

There is also some evidence that marijuana might be an airborne allergen, with individuals becoming sensitized after inhalation of marijuana pollen. They may also become sensitive to airborne hemp dust from industrial processing of the plant.

Airborne allergy symptoms from marijuana are generally similar to the problems caused by any other airborne allergen, such as:

  • Rhinitis or hay fever (itchy, runny nose)
  • Nasal congestion
  • A sore throat
  • Itchy, watery eyes
  • Respiratory problems, such as asthma  

Allergic Reactions to Edibles

Marijuana edibles have become more available for medicinal use as well as places where they are legal for all users. While it is rare, there are reported cases of anaphylaxis reactions with eating hemp seeds.   The symptoms can include ocular symptoms, rash or hives, swelling, shortness of breath, and difficulty speaking.


Many types of pollen from plants, such as ragweed, flowers, and trees, can cause allergic reactions in some people, and marijuana is no different. Marijuana flowers produce pollen that can prove problematic for sensitive individuals, and it can affect the skin or respiratory system.

It is also possible to have an allergic reaction to eating marijuana seeds or marijuana edibles. You may also have an allergy similar to other food allergies when ingesting marijuana-containing products, including rashes and swelling. It may be that your body is allergic to other foods and is cross-reacting to marijuana, and vice versa.

Allergies to tomatoes, peaches, bananas, citrus, grapefruit, eggplant, almonds, and chestnuts have been seen to cross-react with marijuana in various studies.  

Marijuana Use and Sensitization to Other Allergens

A confounding factor in evaluating possible allergies to weed is that it appears that marijuana smoking may sensitize people (stimulate them to develop an allergy to) other antigens.

In one study, marijuana use was associated with the development of allergies to mold, dust mites, plants, and cat dander.   This could mean that a new onset of an allergy is related to sensitization to another allergen, rather than an allergy to weed itself.


Skin testing is the usual way an allergy specialist can pinpoint an allergy. These tests aren’t standardized for marijuana allergy testing, but in theory your allergist could prepare an extract or slurry using the leaves, buds, and flowers of the plant and perform a standard prick test.  

In most cases, your doctor would need to make the diagnosis based on your report of your exposure and symptoms.


If you suspect you have developed a marijuana allergy, it is generally best to avoid the plant altogether. This can be difficult if you are having an airborne exposure that you have no control over.

If you have been using marijuana for medicinal purposes, you might want to speak with your physician and seek professional medical advice. They might be able to suggest alternative treatment options for your condition and symptoms that won’t cause allergic reactions.

If you are unable to avoid marijuana exposure, discuss with your doctor whether to use antihistamines or decongestants for symptoms such as a runny nose and red eyes.

With symptoms of an anaphylactic type of reaction, seek immediate emergency medical care. These reactions can be life-threatening and need to be treated fast.

You may need to carry an Epi-pen in the future if you have an anaphylactic type of reaction.

Learn how to recognize and treat a marijuana allergy by understanding the symptoms and speaking with your physician if these symptoms occur.