Allegra and Multiple sclerosis relapse - a phase IV clinical study of FDA data

Summary:

Multiple sclerosis relapse is reported as a side effect among people who take Allegra (fexofenadine hydrochloride), especially for people who are female, 50-59 old, have been taking the drug for < 1 month also take Ampyra, and have Multiple sclerosis.

The phase IV clinical study analyzes which people have Multiple sclerosis relapse when taking Allegra. It is created by eHealthMe based on reports of 73,095 people who have side effects when taking Allegra from the FDA, and is updated regularly.

What is Allegra?

Allegra has active ingredients of fexofenadine hydrochloride. It is often used in allergies. eHealthMe is studying from 75,498 Allegra users. Check the latest studies of Allegra.

What is Multiple sclerosis relapse?

Multiple sclerosis relapse (reoccurrence of a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath) is found to be associated with 1,029 drugs and 943 conditions by eHealthMe. Check the latest studies of Multiple sclerosis relapse.

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 Aug, 31, 2026

73,095 people reported to have side effects when taking Allegra.
Among them, 161 people (0.22%) have Multiple sclerosis relapse.

Could Allegra cause Multiple sclerosis relapse?

Among these 161 people:

How long have people been on Allegra when they have Multiple sclerosis relapse? *

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What is the gender of people who have Multiple sclerosis relapse when taking Allegra? *

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What is the age of people who have Multiple sclerosis relapse when taking Allegra? *

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* Approximation only. Some reports may have incomplete information.

Do you take Allegra and have Multiple sclerosis relapse?

- Check whether Multiple sclerosis relapse is associated with a drug or a condition
- Predict drug outcomes for up to one year with AI
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Related studies:

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

Allegra (75,498 reports)

Multiple sclerosis relapse treatments and more:

Multiple sclerosis relapse (89,124 reports)

How severe was Multiple sclerosis relapse and when was it recovered:

Multiple sclerosis relapse in Allegra

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

Multiple sclerosis relapse and drugs with ingredients of fexofenadine hydrochloride (242 reports)

Sub-studies by gender and age:

Female: 0-1 2-9 10-19 20-29 30-39 40-49 50-59 60+

Male: 0-1 2-9 10-19 20-29 30-39 40-49 50-59 60+

Browse all side effects of Allegra:

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 Multiple sclerosis relapse:

Multiple sclerosis relapse (1,029 drugs)

Browse all the conditions that are associated with Multiple sclerosis relapse:

Multiple sclerosis relapse (943 conditions)

How the study uses the data?

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