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Taking Benadryl & Suboxone: Are There Serious Dangers?

Elena Hill, MD, MPH profile image
Medically Reviewed By Elena Hill, MD, MPH • Updated Aug 2, 2023

Benadryl is an over the counter allergy medication. It can cause some sleepiness and sedation. Suboxone can also cause some sleepiness. If used in combination, patients can become overly sleepy or sedated, which can be dangerous. While some people do take these medications together, you should do so with caution and consult your doctor prior to doing so.

Never combine medications (either prescription or over-the-counter solutions) with Suboxone without checking with your doctor first. 

What Is Benadryl?

The over-the-counter drug Benadryl contains diphenhydramine. This medication can be used to treat the following:[1]

  • Itchy and watery eyes
  • Sneezing
  • Mild coughs
  • Motion sickness

Diphenhydramine can cause sedation.[2] As a result, some people use this medication for temporary insomnia. 

When two sedating drugs combine, the results can be unpredictable. Thus, using Benadryl in combination with Suboxone can increase sleepiness and sedation and potentially be dangerous.

Side Effects of Taking Benadryl & Suboxone

What Side Effects Are Caused by Benadryl & Suboxone?

Both Benadryl and Suboxone have side effects. 

Benadryl’s Side Effects

Diphenhydramine has some side effects including:[1]

  • Anorexia
  • Constipation
  • Dizziness
  • Drowsiness
  • Dry mouth and throat
  • Nausea

Suboxone’s Side Effects

Suboxone can also cause side effects, including these:[3]

  • Blurry vision
  • Constipation or abominable pain 
  • Headaches
  • Sedation/sleepiness 
  • Mouth numbing
  • Tongue pain

Combined Medications Side Effects

When combining Suboxone and Benadryl, you can develop severe sedation.[4] The two drugs work together on the central nervous system, slowing your breathing to such a degree that it stops altogether. You could be at risk for being overly sedated which can lead to falls, accidents, or even respiratory depression or overdose. 

Will Benadryl & Suboxone Affect Your Mental Health?

Sedation can impact the way you think and feel. A low energy level could leave you feeling slow, sad, and depressed. The longer you take both medications simultaneously, the stronger these feelings can become.

Diphenhydramine can also cause cognitive decline. In studies, people taking this drug felt sleepy, and they had poorer rates of the following:[5]

  • Attention
  • Working memory
  • Vigilance

Combining your Benadryl dose with Suboxone could worsen these problems.

Can You Overdose on Both Drugs?

Yes, potentially. Between 2019 and 2020, about 14% of opioid overdose deaths also involved antihistamines, including diphenhydramine (Benadryl).[6] 

Some people do take these medications together, but doing so should be done with caution and under the supervision of a doctor. 

Alternatives to Benadryl

Plenty of people struggle with sniffles, sneezes, and discomfort from allergies and colds. While diphenhydramine may not be safe, plenty of other options exist, including:[7]

  • Other antihistamines: There are other anti-allergy drugs such as Loratidine or Allegra that are less sedating than Benadryl 
  • Corticosteroids: In extreme cases patients can use steroids to decrease allergy symptoms 
  • Decongestants: Sprays and nasal drops can also be non-sedating alternatives for allergies.

Your doctor can help you find a solution that works for you. 

Talk to Your Doctor

Take your Suboxone therapy seriously, and don’t combine your medication with other sedating medications when possible. Talk to your doctor before adding anything, including Benadryl, to your Suboxone therapy.


  1. Diphenhydramine. National Library of Medicine. January 2022. Accessed November 2022.
  2. A Qualitative Study of Diphenhydramine Injection in Kyrgyz Prisons and Implications for Harm Reduction. Harm Reduction Journal. October 2020. Accessed November 2022.
  3. Buprenorphine Sublingual and Buccal (Opioid Dependence). National Library of Medicine. January 2022. Accessed November 2022.
  4. Drug Interactions of Clinical Importance Among the Opioids, Methadone, Buprenorphine, and Other Frequently Prescribed Medications: A Review. American Journal of Addiction. April 2022. Accessed November 2022.
  5. Initial and Steady-State Effects of Diphenhydramine and Loratadine on Sedation, Cognition, Mood, and Psychomotor Performance. JAMA. November 1997. Accessed November 2022.
  6. Notes from the Field: Antihistamine Positivity and Involvement in Drug Overdose Deaths — 44 Jurisdictions, United States, 2019–2020. Centers for Disease Control and Prevention. October 2022. Accessed November 2022.
  7. Is America Over-Medicating on Allergy Medicine? Molekule. December 2018. Accessed November 2022.

Medically Reviewed By Elena Hill, MD, MPH

Elena Hill, MD; MPH received her MD and Masters of Public Health degrees at Tufts Medical School and completed her family medicine residency at Boston Medical Center. She is currently an attending physician at Bronxcare Health Systems in the Bronx, NY where ... Read More

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