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Diphenhydramine is an antihistamine often used to treat allergies, insomnia, and other conditions. However, there has been an alarming rise in diphenhydramine misuse in recent years, particularly among young people. The “Benadryl Challenge” on TikTok led the FDA to put out a statement in 2020 warning about the risk of using high doses.

What is Diphenhydramine?

Diphenhydramine (also known as DPH, Dimedrol, and Benadryl) is an antihistamine commonly used to treat allergy symptoms such as itching, sneezing, and runny nose. It is also used as a sleep aid and to treat other conditions such as motion sickness and Parkinson’s disease.

What are the Risks of Diphenhydramine Misuse?

Diphenhydramine is often misused in two ways, to induce sleep and to experience euphoria. Misusing diphenhydramine can have serious consequences. When taken in large doses, it can cause hallucinations, delirium, and seizures. It can also cause rapid heartbeat, high blood pressure, and difficulty breathing. In some cases, it can even be fatal.

In addition to the physical risks, diphenhydramine misuse can also have psychological effects. People who misuse the drug may experience anxiety, paranoia, and other mental health issues.

Are There Drug Tests for Diphenhydramine?

Yes. Though diphenhydramine is a legal substance, like alcohol, misuse can become a larger problem for some individuals, especially if they are in legal programs to get on the road to recovery. In these circumstances, drug testing for any mind-altering drug might be a consideration regardless of its status as legal or illicit. 

USDTL offers diphenhydramine testing in hair and nail specimens to organizations that administer drug testing. Diphenhydramine can build up and remain in hair and nail specimens for up to approximately three months. 

If your organization would benefit from offering this type of detection, please get in touch with us at 1-800-235-2367 or fill out our contact us form. Please note we are a business-to-business forensic laboratory only, and we do not offer toxicology testing to the general public. Due to confidentiality obligations, we cannot answer questions from parties not explicitly authorized by our business-to-business clients.


1. U.S. Food and Drug Administration. (2019). Diphenhydramine (Benadryl): Drug Safety Communication – Serious Problems with High Doses from Over-the-Counter (OTC) Use. Retrieved from

2. National Institute on Drug Abuse. (2021). Misuse of Prescription Drugs. Retrieved from

3. Substance Abuse and Mental Health Services Administration. (2020). Key Substance Use and Mental Health Indicators in the United States: Results from the 2019 National Survey on Drug Use and Health. Retrieved from

4. American Academy of Pediatrics. (2019). Diphenhydramine (Benadryl). In: Kimberlin DW, Brady MT, Jackson MA, Long SS, eds. Red Book: 2018 Report of the Committee on Infectious Diseases. 31st ed. Elk Grove Village, IL: American Academy of Pediatrics; 2019:364-365.

5. Drug Enforcement Administration. (2021). Drugs of Abuse: A DEA Resource Guide. Retrieved from



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