Flexeril and Injection site vesicles - a phase IV clinical study of FDA data

Summary:

Injection site vesicles is reported as a side effect among people who take Flexeril (cyclobenzaprine hydrochloride), especially for people who are female, 50-59 old, also take Humira, and have Rheumatoid arthritis.

The phase IV clinical study analyzes which people have Injection site vesicles when taking Flexeril. It is created by eHealthMe based on reports of 34,789 people who have side effects when taking Flexeril from the FDA, and is updated regularly.

What is Flexeril?

Flexeril has active ingredients of cyclobenzaprine hydrochloride. It is often used in muscle spasms. eHealthMe is studying from 38,308 Flexeril users. Check the latest studies of Flexeril.

What is Injection site vesicles?

Injection site vesicles (fluid- or air-filled cavity or sac at injection site) is found to be associated with 299 drugs and 387 conditions by eHealthMe. Check the latest studies of Injection site vesicles.

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, 01, 2026

34,789 people reported to have side effects when taking Flexeril.
Among them, 12 people (0.03%) have Injection site vesicles.

Could Flexeril cause Injection site vesicles?

Among these 12 people:

What is the gender of people who have Injection site vesicles when taking Flexeril? *

female: 100 %
male: 0.0 %

What is the age of people who have Injection site vesicles when taking Flexeril? *

What are other drugs people take besides Flexeril? *

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

Injection Site Pain: 7 people, 58.33%
Joint Pain: 4 people, 33.33%
Mobility Decreased (ability to move is reduced): 3 people, 25.00%
Injection Site Rash: 3 people, 25.00%
Injection Site Pruritus (severe itching at injection site): 3 people, 25.00%
Injection Site Erythema (redness at injection site): 3 people, 25.00%
Injection Site Haemorrhage (bleeding from injection site): 2 people, 16.67%
Joint Swelling: 2 people, 16.67%
Injection Site Swelling: 2 people, 16.67%
Swelling: 2 people, 16.67%

What are the existing conditions these people have? *

Rheumatoid Arthritis (a chronic progressive disease causing inflammation in the joints): 6 people, 50.00%
Injection Site Pain: 2 people, 16.67%
Nerve Injury: 1 person, 8.33%
High Blood Cholesterol: 1 person, 8.33%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 1 person, 8.33%
Diabetes: 1 person, 8.33%
Crohn's Disease (a condition that causes inflammation of the gastrointestinal tract): 1 person, 8.33%
Blood Pressure Abnormal: 1 person, 8.33%
Birth Control: 1 person, 8.33%
Ankylosing Spondylitis (type of arthritis affecting the spine): 1 person, 8.33%

* Approximation only. Some reports may have incomplete information.

Do you take Flexeril and have Injection site vesicles?

- Check whether Injection site vesicles 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 Flexeril:

Flexeril (38,308 reports)

Browse all side effects of Flexeril:

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 vesicles:

Injection site vesicles (299 drugs)

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

Injection site vesicles (387 conditions)

How the study uses the data?

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