Benadryl and Cluster headache - a phase IV clinical study of FDA data

Summary:

Cluster headache is reported as a side effect among people who take Benadryl (diphenhydramine hydrochloride), especially for people who are female, 40-49 old, also take Singulair, and have Generalized anxiety disorder.

The phase IV clinical study analyzes which people have Cluster headache when taking Benadryl. It is created by eHealthMe based on reports of 100,139 people who have side effects when taking Benadryl from the FDA, and is updated regularly.

What is Benadryl?

Benadryl has active ingredients of diphenhydramine hydrochloride. It is often used in allergies. eHealthMe is studying from 104,956 Benadryl users. Check the latest studies of Benadryl.

What is Cluster headache?

Cluster headache (one-sided head pain with tearing) is found to be associated with 237 drugs and 385 conditions by eHealthMe. Check the latest studies of Cluster headache.

eHealthMe: drug outcomes in the real world

eHealthMe runs one of the largest post-marketing drug safety studies in the world. We study millions of patients and 5,000 more each day. Our data-driven phase IV clinical trials have been referenced on 800+ peer-reviewed medical publications including The Lancet, Mayo Clinic Proceedings, and Nature. Tools to study our phase IV findings are available to the public, anonymous and free >>>.

On Sep, 02, 2026

100,139 people reported to have side effects when taking Benadryl.
Among them, 13 people (0.01%) have Cluster headache.

Among these 13 people:

What is the gender of people who have Cluster headache when taking Benadryl? *

female: 92.31 %
male: 7.69 %

What is the age of people who have Cluster headache when taking Benadryl? *

What are other drugs people take besides Benadryl? *

Claritin: 6 people, 46.15%
Hydroxyzine: 6 people, 46.15%
Singulair: 6 people, 46.15%
Desoximetasone: 3 people, 23.08%
Epinephrine: 3 people, 23.08%
Escitalopram: 3 people, 23.08%
Magnesium Oxide: 2 people, 15.38%
Cetirizine Hydrochloride: 2 people, 15.38%
Prozac: 2 people, 15.38%
Prilosec: 2 people, 15.38%

What are other side effects people have besides Cluster headache? *

Fatigue (feeling of tiredness): 9 people, 69.23%
Drug Ineffective: 8 people, 61.54%
Paraesthesia (sensation of tingling, tickling, prickling, pricking, or burning of a person's skin with no apparent long-term physical effect): 7 people, 53.85%
Weight Increased: 6 people, 46.15%
Drug Hypersensitivity: 6 people, 46.15%
Anaemia (lack of blood): 6 people, 46.15%
High Blood Pressure: 6 people, 46.15%
Urticaria (rash of round, red welts on the skin that itch intensely): 6 people, 46.15%
Arrhythmias (irregular heartbeat): 6 people, 46.15%
Heart Palpitations (feelings or sensations that your heart is pounding or racing): 6 people, 46.15%

What are the existing conditions these people have? *

Generalized Anxiety Disorder (excessive, uncontrollable, unexplained and often irrational worry): 6 people, 46.15%
Crohn's Disease (a condition that causes inflammation of the gastrointestinal tract): 2 people, 15.38%
Depression: 2 people, 15.38%
Narcolepsy (brain's inability to regulate sleep-wake cycles normally): 2 people, 15.38%
Ulcer Haemorrhage (bleeding ulcer): 1 person, 7.69%
Joint Pain: 1 person, 7.69%
Arthritis (form of joint disorder that involves inflammation of one or more joints): 1 person, 7.69%
Central Nervous System Lymphoma (cancer of central nervous system forms in lymph tissue): 1 person, 7.69%
Heart Attack: 1 person, 7.69%
High Blood Cholesterol: 1 person, 7.69%

* Approximation only. Some reports may have incomplete information.

Do you take Benadryl and have Cluster headache?

- Check whether Cluster headache is associated with a drug or a condition
- Predict drug outcomes for up to one year with AI
- Get an AI agent to monitor your drugs continuously

Related studies:

Effectiveness of, long term effects of, and alternative drugs to Benadryl:

Benadryl (104,956 reports)

Browse all side effects of Benadryl:

a b c d e f g h i j k l m n o p q r s t u v w x y z

Browse all the drugs that are associated with Cluster headache:

Cluster headache (237 drugs)

Browse all the conditions that are associated with Cluster headache:

Cluster headache (385 conditions)

How the study uses the data?

The study uses data from the FDA. It is based on diphenhydramine hydrochloride (the active ingredients of Benadryl) and Benadryl (the brand name). Other drugs that have the same active ingredients (e.g. generic drugs) are not considered. Dosage of drugs is not considered in the study.

How to use the study?

DO NOT STOP MEDICATIONS without first consulting your doctor. If there are any serious or long term adverse effects discovered in the study, discuss the study with your doctor to ensure that proper medication management will be in place if applicable.

Who is eHealthMe?

With medical big data and proven AI/ML algorithms, eHealthMe provides a platform for everyone to run phase IV clinical trials. We study millions of patients and 5,000 more each day. Results of our real-world drug study have been referenced on 800+ peer-reviewed medical publications, including The Lancet, Mayo Clinic Proceedings, and Nature. Our analysis results are available to researchers, health care professionals, patients (testimonials), and software developers (open API).

WARNING, DISCLAIMER, USE FOR PUBLICATION

WARNING: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on eHealthMe.com is for informational purposes only, and is not a substitute for medical advice, diagnosis, or treatment provided by a qualified healthcare provider. All information is observation-only. Our phase IV clinical studies alone cannot establish cause-effect relationship. Different individuals may respond to medication in different ways. Every effort has been made to ensure that all information is accurate, up-to-date, and complete, but no guarantee is made to that effect. The use of the eHealthMe site and its content is at your own risk.

If you use this eHealthMe study on publication, please acknowledge it with a citation: study title, URL, accessed date.