Diphen and Decreased activity - a phase IV clinical study of FDA data

Summary:

Decreased activity is reported as a side effect among people who take Diphen (diphenhydramine hydrochloride), especially for people who are male, 60+ old, have been taking the drug for 6 - 12 months also take Acetaminophen, and have Rheumatoid arthritis.

The phase IV clinical study analyzes which people have Decreased activity when taking Diphen. It is created by eHealthMe based on reports of 113,958 people who have side effects when taking Diphen from the FDA, and is updated regularly.

What is Diphen?

Diphen has active ingredients of diphenhydramine hydrochloride. It is often used in insomnia. eHealthMe is studying from 115,429 Diphen users. Check the latest studies of Diphen.

What is Decreased activity?

Decreased activity is found to be associated with 1,276 drugs and 1,306 conditions by eHealthMe. Check the latest studies of Decreased activity.

On Nov, 15, 2025

113,958 people reported to have side effects when taking Diphen.
Among them, 111 people (0.1%) have Decreased activity.

Among these 111 people:

How long have people been on Diphen when they have Decreased activity? *

What is the gender of people who have Decreased activity when taking Diphen? *

female: 44.71 %
male: 55.29 %

What is the age of people who have Decreased activity when taking Diphen? *

What are other drugs people take besides Diphen? *

What are other side effects people have besides Decreased activity? *

Pain: 58 people, 52.25%
High Blood Pressure: 44 people, 39.64%
Joint Pain: 41 people, 36.94%
Infusion Related Reaction: 41 people, 36.94%
Arthritis (form of joint disorder that involves inflammation of one or more joints): 36 people, 32.43%
Dyspnea (difficult or laboured breathing): 36 people, 32.43%
Pain In Extremity: 36 people, 32.43%
Dizziness: 33 people, 29.73%
Weight Decreased: 33 people, 29.73%
Paraesthesia (sensation of tingling, tickling, prickling, pricking, or burning of a person's skin with no apparent long-term physical effect): 32 people, 28.83%

What are the existing conditions these people have? *

Rheumatoid Arthritis (a chronic progressive disease causing inflammation in the joints): 41 people, 36.94%
Hiv Infection: 28 people, 25.23%
High Blood Pressure: 27 people, 24.32%
Restless Leg Syndrome (a powerful urge to move your legs): 13 people, 11.71%
Pain: 13 people, 11.71%
Blood Iron Decreased: 11 people, 9.91%
Hypersensitivity: 11 people, 9.91%
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): 11 people, 9.91%
Idiopathic Pulmonary Fibrosis (chronic lung disease): 10 people, 9.01%
High Blood Cholesterol: 9 people, 8.11%

* Approximation only. Some reports may have incomplete information.

Do you take Diphen and have Decreased activity?

- Check whether Decreased activity is associated with a drug or a condition
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Related studies:

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

Diphen (115,429 reports)

Common Diphen side effects:

Browse all side effects of Diphen:

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

Common drugs associated with Decreased activity:

Browse all the drugs that are associated with Decreased activity:

Decreased activity (1,276 drugs)

Common conditions associated with Decreased activity:

Ovarian cancer: 908 reports
Asthma: 689 reports
Bronchial asthma: 688 reports
Hiv infection: 679 reports
Human immunodeficiency virus infection: 678 reports
Hypertension aggravated: 514 reports
Blood pressure increased: 510 reports
Depression: 462 reports
Antidepressant therapy: 457 reports
Pain exacerbated: 446 reports

Browse all the conditions that are associated with Decreased activity:

Decreased activity (1,306 conditions)

Drugs similar to Diphen and Decreased activity :

How the study uses the data?

The study uses data from the FDA. It is based on diphenhydramine hydrochloride (the active ingredients of Diphen) and Diphen (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.