Should you use marijuana if you take Benadryl?

Using cannabis and diphenhydramine (Benadryl) together may be safe in small doses, but is generally not recommended. Combining them may increase your risk of certain side effects, such as drowsiness and dizziness. Taking them together can also make their effects last for longer than desired.  

So if you take Benadryl, it’s important to proceed with caution while using cannabis. 

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What is Benadryl?

Benadryl is an over-the-counter antihistamine, a common type of allergy medication. It may also be used to help with:

• Sleep difficulties
• Motion sickness
• Some cold and flu symptoms
• Parkinson’s disease (limited use)

How does Benadryl work?

Histamine is a compound in your body that triggers inflammation when you’re exposed to certain allergens, such as:

• Pollen
• Pet dander
• Certain foods

Antihistamines like Benadryl block histamines in your body to prevent allergy symptoms like sneezing, runny nose, and coughing.

Benadryl is generally considered safe. But it can cause side effects, including:

• Drowsiness
• Dizziness
• Headache
• Impaired motor skills
• Euphoria
• Blurred vision
• Urinary retention
• Erectile dysfunction
• Confusion
• Fast heartbeat

Prolonged use of Benadryl, especially in older adults, may carry additional risks such as confusion or memory problems.

To lower your risk of side effects, take the dose recommended by your doctor or the amount listed on the medication label.

Is it safe to take Benadryl and weed?

Combining low doses of cannabis and Benadryl may generally be safe under your doctor’s guidance, but it still comes with certain risks. 

Mixing cannabis and Benadryl can increase your risk of certain side effects, such as:

• Drowsiness
• Dizziness
• Impaired motor skills
• Headache
• Confusion
• Fast heartbeat
• Slow breathing (respiratory depression)

Both substances can be sedating, so avoid driving after taking them together.

Cannabis may inhibit the levels of liver enzymes that help your body break down and metabolize medications like Benadryl. This leads to increased levels of medication in the bloodstream. As a result, combining them may cause their effects to last for longer than intended. It can also make their effects feel stronger.

Before you combine cannabis with Benadryl, it’s best to talk to your doctor to establish a safe dosing plan.

Can you take Benadryl after taking CBD?

Cannabidiol (CBD) is a non-intoxicating cannabis compound. It’s commonly used to help treat health issues such as:

• Pain
• Inflammation
• Anxiety
• Insomnia

Like other cannabis compounds, CBD can inhibit liver enzymes that help metabolize Benadryl. CBD can also cause drowsiness, which may add to the sedating effects of Benadryl.

That said, it’s best to speak with your doctor before mixing CBD and Benadryl.

How to take Benadryl and marijuana

If you’re a cannabis user seeking allergy relief, ask your doctor if it’s safe to combine cannabis with Benadryl. 

You can also follow these safety tips: 

• Dose as directed: Take the recommended dosage amounts of both cannabis and Benadryl to minimize your risk of side effects. 
• Time each dose wisely: Avoid having both substances peak in your system at the same time. The effects of Benadryl can peak within 1 to 2 hours and last for 4 to 6 hours. When inhaled, the effects of cannabis can peak in under 15 minutes and last for 2 to 3 hours. Cannabis edibles can peak within 1 to 2 hours and last for 8 to 10 hours. 

• Consider your other medications: If you’re taking other medications, ask your doctor if it’s safe to combine them with cannabis and Benadryl.

The takeaway: Combining cannabis and Benadryl may increase your risk of side effects

Cannabis and Benadryl may interact with one another, especially if both are taken in high doses. Combining them may increase your risk of side effects like drowsiness and confusion.

To lower your risk of side effects, consult with your doctor or a Leafwell provider to determine a dosing schedule and learn how to use them together safely.

Resources

• Antihistamines. https://www.ncbi.nlm.nih.gov/books/NBK538188/
• Cannabidiol, a major phytocannabinoid, as a potent atypical inhibitor for CYP2D6. https://pubmed.ncbi.nlm.nih.gov/21821735/
• Differential interactions of selected phytocannabinoids with human CYP2D6 polymorphisms. https://pmc.ncbi.nlm.nih.gov/articles/PMC8455456/
• Diphenhydramine. https://www.ncbi.nlm.nih.gov/books/NBK526010/
• Identification of human cytochrome P450 isozymes involved in diphenhydramine N-demethylation. https://pubmed.ncbi.nlm.nih.gov/17020955/
• Part 2: Drug interactions involving cannabis products in persons aged 18 and over: A summary of published case reports and analysis of the FDA adverse event reporting system. https://bpspubs.onlinelibrary.wiley.com/doi/10.1002/prp2.70047