Tysabri and Injection site mass - a phase IV clinical study of FDA data

Summary:

Injection site mass is reported as a side effect among people who take Tysabri (natalizumab), especially for people who are female, 40-49 old, have been taking the drug for 2 - 5 years also take Avonex, and have Gait disturbance.

The phase IV clinical study analyzes which people have Injection site mass when taking Tysabri. It is created by eHealthMe based on reports of 220,870 people who have side effects when taking Tysabri from the FDA, and is updated regularly.

What is Tysabri?

Tysabri has active ingredients of natalizumab. It is often used in multiple sclerosis. eHealthMe is studying from 221,369 Tysabri users. Check the latest studies of Tysabri.

What is Injection site mass?

Injection site mass is found to be associated with 831 drugs and 787 conditions by eHealthMe. Check the latest studies of Injection site mass.

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

220,870 people reported to have side effects when taking Tysabri.
Among them, 36 people (0.02%) have Injection site mass.

Could Tysabri cause Injection site mass?

Among these 36 people:

How long have people been on Tysabri when they have Injection site mass? *

What is the gender of people who have Injection site mass when taking Tysabri? *

female: 94.29 %
male: 5.71 %

What is the age of people who have Injection site mass when taking Tysabri? *

What are other drugs people take besides Tysabri? *

What are other side effects people have besides Injection site mass? *

Gait Disturbance: 7 people, 19.44%
Injection Site Erythema (redness at injection site): 7 people, 19.44%
Injection Site Pain: 6 people, 16.67%
Stress And Anxiety: 6 people, 16.67%
Hypoaesthesia (reduced sense of touch or sensation): 6 people, 16.67%
Pain: 6 people, 16.67%
Rashes (redness): 6 people, 16.67%
Fatigue (feeling of tiredness): 6 people, 16.67%
Weakness: 6 people, 16.67%
Pain In Extremity: 5 people, 13.89%

What are the existing conditions these people have? *

Gait Disturbance: 3 people, 8.33%
Sleep Disorder: 1 person, 2.78%
Seasonal Allergy (allergic condition due to certain season): 1 person, 2.78%
Rheumatoid Arthritis (a chronic progressive disease causing inflammation in the joints): 1 person, 2.78%
Neuroendocrine Tumor: 1 person, 2.78%
Ankylosing Spondylitis (type of arthritis affecting the spine): 1 person, 2.78%

* Approximation only. Some reports may have incomplete information.

Do you take Tysabri and have Injection site mass?

- Check whether Injection site mass 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 Tysabri:

Tysabri (221,369 reports)

Browse all side effects of Tysabri:

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 Injection site mass:

Injection site mass (831 drugs)

Browse all the conditions that are associated with Injection site mass:

Injection site mass (787 conditions)

How the study uses the data?

The study uses data from the FDA. It is based on natalizumab (the active ingredients of Tysabri) and Tysabri (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.