Benadryl (diphenhydramine) is one of the most widely used allergy medications in the US, with over 1.5 million prescriptions filled annually, and even more Americans purchasing it over-the-counter. In 2023, the diphenhydramine market alone generated over $400 million, highlighting the number of Americans purchasing the drug [1].
Long-term use can cause physical dependence and lead to uncomfortable withdrawal symptoms such as nausea, vomiting, and anxiety.
What is Benadryl?
Benadryl (diphenhydramine) is an over-the-counter (OTC) antihistamine medication used to treat symptoms of allergies and the common cold, such as sneezing, runny nose, watery eyes, and skin rash. Benadryl is FDA-approved to treat the following conditions:
- Allergic reactions such as insect bites, hives, and hay fever
- Prevention and treatment of motion sickness
- Adjunctive therapy for patients with Parkinsons
- Topical Benadryl may be used for minor cuts, burns, or rashes, such as poison ivy
Off-label, many users take it to relieve anxiety or as a sleep aid. It is not recommended for OTC use to self-medicate for sleep/anxiety, but under the supervision of a doctor who is prescribing the medication, then it can be safely used for these symptoms.
How Does Benadryl Affect The Brain?
Benadryl blocks histamine receptors and acetylcholine neurotransmitters in the brain, reducing the body’s “alertness” signals and contributing to sedation and relaxation. It easily crosses the blood-brain barrier, with some users feeling its effects in as little as 15 to 30 minutes [2].
Benadryl can cause several distressing side effects on the brain and body, especially when misused, which include:
- Morning grogginess
- Memory loss
- Lack of motivation or trouble focusing
- Weight gain, water retention
- Blurry vision, dizziness
- Urinary retention
- Hallucinations at higher doses (many report seeing bugs crawling on the ceiling or a dark figure referred to as the “hat man”) [3]
Can You Get Addicted To Benadryl?
Yes, Benadryl can become addictive. Although not as potent as other drugs, its sedative effects can lead to abuse and dependency. At low doses, Benadryl promotes relaxation and sedation, while at higher doses it can produce euphoria and mild hallucinations or dissociative effects (e.g., feeling out of body).
Other factors contributing to Benadryl addiction include [2]:
- Psychological dependence: Users often develop cravings for Benadryl, especially if they use it to cope with symptoms of anxiety, stress, or sleep challenges.
- Dopamine and Reward Pathways: Benadryl can interrupt reward pathways in the dopamine system, reinforcing drug-seeking behavior and creating a cycle of addiction that is difficult to quit without professional intervention.
- Perception of Safety: Many users think over-the-counter medications are automatically safe and underestimate their risk potential for abuse.
Understanding Benadryl Withdrawal
Long-term misuse can cause physical dependence and withdrawal symptoms when quitting the drug. Benadryl withdrawal symptoms can affect both mental and physical health. Although not usually life-threatening, they can be uncomfortable and challenging to manage without support.
Benadryl Withdrawal Symptoms
Below are some common withdrawal symptoms of Benadryl:
- Nausea, vomiting, diarrhea
- Cold sweats
- Dizziness
- Blurry vision
- Increased anxiety, depression
- Insomnia
- Severe symptoms may include hypertension, tachycardia, and increased urgency to urinate.
How Long Does Withdrawal Last?
Benadryl withdrawal can last anywhere from a few days to several weeks, with effects such as anxiety and insomnia lasting for months. Symptoms of Benadryl withdrawal usually begin 12 to 24 hours after the last dose of the drug and peak within 1 to 3 days.
The withdrawal timeline looks different for individuals based on several factors, including:
- Frequency and dose
- Height, weight, gender
- Polydrug use (mixing Benadryl with other drugs or alcohol to increase sedative effects)
- Underlying health conditions
- Presence of social support
Managing Benadryl Withdrawal Symptoms
It is possible to stop Benadryl use at home, but it should be done with caution. There are several strategies that can help ease withdrawal symptoms and encourage long-term recovery. Some of these include:
- Taper Off: Reduce your dose over time and speak to a healthcare professional for the best guidance.
- Sleep Hygiene: Insomnia is a common withdrawal symptom of Benadryl, so avoid caffeine, manage stress, turn your phone off before bed, and do yoga to wind down in the evenings.
- Stay Hydrated: Abusing antihistamines can dry out the nasal passageways, throat, and mouth. Drink plenty of water to support your body as it adjusts back to base level.
- Physical Comfort and Stress Management: Take it extra easy during this period to manage stress or physical discomfort. Take a hot bath, do yoga, get a massage, or use a heating pad to relieve muscle tension and aches.
- Social support: Let someone close to you know you’re self-detoxing from Benadryl. They can help you through the process and provide a distraction during craving periods.
Military Informed Treatment for OTC Addiction
Miramar Health is a veteran-owned and operated recovery program providing trauma-informed care for veterans. Our mission is to free veterans from America’s mental health and addiction crisis and to empower them to create a better future for themselves and their families.
We provide a comprehensive blend of evidence-based therapies, holistic healing activities, and social support to address OTC abuse and co-occurring mental health disorders in veterans. Get in touch with our Admissions team today!
Sources
[1] Gore, A. 2025. Diphenhydramine Market Report. Cognitive Market Research.
[2] Selioutski, O. (2017). Chronic diphenhydramine abuse and withdrawal: A diagnostic challenge. Neurology. Clinical practice, 7(5), 439–441.
[3] Pope, C. 2025. What is the Benadryl hat man? Drugs.com.