Benadryl and Ventricular fibrillation - a phase IV clinical study of FDA data


Ventricular fibrillation is found among people who take Benadryl, especially for people who are male, 60+ old, have been taking the drug for < 1 month.

The phase IV clinical study analyzes which people take Benadryl and have Ventricular fibrillation. It is created by eHealthMe based on reports of 85,073 people who have side effects when taking Benadryl from the FDA, and is updated regularly. You can use the study as a second opinion to make health care decisions.

Phase IV trials are used to detect adverse drug outcomes and monitor drug effectiveness in the real world. With medical big data and AI algorithms, eHealthMe is running millions of phase IV trials and makes the results available to the public. Our original studies have been referenced on 600+ medical publications including The Lancet, Mayo Clinic Proceedings, and Nature.

On Oct, 01, 2022

85,073 people reported to have side effects when taking Benadryl.
Among them, 81 people (0.1%) have Ventricular fibrillation.

What is Benadryl?

Benadryl has active ingredients of diphenhydramine hydrochloride. It is often used in allergies. eHealthMe is studying from 89,693 Benadryl users for its effectiveness, alternative drugs and more.

What is Ventricular fibrillation?

Ventricular fibrillation (abnormally irregular heart rhythm) is found to be associated with 1,756 drugs and 1,200 conditions by eHealthMe.

Number of Benadryl and Ventricular fibrillation reports submitted per year:

Could Benadryl cause Ventricular fibrillation?

Time on Benadryl when people have Ventricular fibrillation *:

  • < 1 month: 100 %
  • 1 - 6 months: 0.0 %
  • 6 - 12 months: 0.0 %
  • 1 - 2 years: 0.0 %
  • 2 - 5 years: 0.0 %
  • 5 - 10 years: 0.0 %
  • 10+ years: 0.0 %

Gender of people who have Ventricular fibrillation when taking Benadryl *:

  • female: 47.95 %
  • male: 52.05 %

Age of people who have Ventricular fibrillation when taking Benadryl *:

  • 0-1: 0.0 %
  • 2-9: 0.0 %
  • 10-19: 0.0 %
  • 20-29: 4.29 %
  • 30-39: 7.14 %
  • 40-49: 7.14 %
  • 50-59: 10.0 %
  • 60+: 71.43 %

Common drugs people take besides Benadryl *:

  1. Tylenol: 26 people, 32.10%
  2. Zofran: 17 people, 20.99%
  3. Lasix: 16 people, 19.75%
  4. Prednisone: 15 people, 18.52%
  5. Decadron: 14 people, 17.28%
  6. Acetaminophen: 13 people, 16.05%
  7. Versed: 13 people, 16.05%
  8. Folic Acid: 13 people, 16.05%
  9. Albuterol: 12 people, 14.81%
  10. Lopressor: 12 people, 14.81%

Common side effects people have besides Ventricular fibrillation *:

  1. Cardiac Arrest: 34 people, 41.98%
  2. Hypotension (abnormally low blood pressure): 27 people, 33.33%
  3. Ventricular Tachycardia (rapid heartbeat that originates in one of the lower chambers (the ventricles) of the heart): 18 people, 22.22%
  4. Arrhythmias (irregular heartbeat): 14 people, 17.28%
  5. Heart Rate Increased: 14 people, 17.28%
  6. Chest Pain: 14 people, 17.28%
  7. Oxygen Saturation Decreased: 13 people, 16.05%
  8. Stress And Anxiety: 13 people, 16.05%
  9. Blood Pressure Diastolic Decreased: 12 people, 14.81%
  10. Blood Pressure Fluctuation: 12 people, 14.81%

Common conditions people have *:

  1. Rheumatoid Arthritis (a chronic progressive disease causing inflammation in the joints): 7 people, 8.64%
  2. Systemic Sclerosis (Scleroderma) (an autoimmune or connective tissue disease. it is characterized by thickening of the skin): 6 people, 7.41%
  3. Myositis (inflammation of the muscles): 6 people, 7.41%
  4. Raynaud's Phenomenon (discoloration of the fingers, toes, and occasionally other areas): 6 people, 7.41%
  5. Atrial Fibrillation/flutter (atrial fibrillation and flutter are abnormal heart rhythms in which the atria, or upper chambers of the heart, are out of sync with the ventricles): 4 people, 4.94%
  6. Acute Myeloid Leukaemia (acute cancer in which the bone marrow makes abnormal myeloblasts): 3 people, 3.70%
  7. Idiopathic Thrombocytopenic Purpura (bleeding disorder in which the immune system destroys platelets, which are necessary for normal blood clotting): 3 people, 3.70%
  8. Pain: 3 people, 3.70%
  9. Nausea (feeling of having an urge to vomit): 3 people, 3.70%
  10. Appetite - Decreased (decreased appetite occurs when you have a reduced desire to eat): 2 people, 2.47%

* Approximation only. Some reports may have incomplete information.

Do you take Benadryl and have Ventricular fibrillation?

Check whether Ventricular fibrillation is associated with a drug or a condition

How to use the study?

You can discuss the study with your doctor, to ensure that all drug risks and benefits are fully discussed and understood.

Related studies

How severe was Ventricular fibrillation and when was it recovered:

Expand to all the drugs that have ingredients of diphenhydramine hydrochloride:

Alternative drugs to, pros and cons of Benadryl:

Common Benadryl side effects:

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

Ventricular fibrillation treatments and more:

COVID vaccines that are related to Ventricular fibrillation:

Common drugs associated with Ventricular fibrillation:

All the drugs that are associated with Ventricular fibrillation:

Common conditions associated with Ventricular fibrillation:

All the conditions that are associated with Ventricular fibrillation:

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.

Who is eHealthMe?

With medical big data and proven AI 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 600+ 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: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on 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.

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