Fentanyl and Hyperreflexia - a phase IV clinical study of FDA data

Summary:

Hyperreflexia is reported as a side effect among people who take Fentanyl (fentanyl citrate), especially for people who are female, 60+ old, have been taking the drug for < 1 month also take Propofol, and have Depression.

The phase IV clinical study analyzes which people have Hyperreflexia when taking Fentanyl. It is created by eHealthMe based on reports of 72,646 people who have side effects when taking Fentanyl from the FDA, and is updated regularly.

What is Fentanyl?

Fentanyl has active ingredients of fentanyl citrate. It is often used in pain. eHealthMe is studying from 73,301 Fentanyl users. Check the latest studies of Fentanyl.

What is Hyperreflexia?

Hyperreflexia (overactive or over responsive reflexes) is found to be associated with 422 drugs and 650 conditions by eHealthMe. Check the latest studies of Hyperreflexia.

On Aug, 01, 2026

72,646 people reported to have side effects when taking Fentanyl.
Among them, 73 people (0.1%) have Hyperreflexia.

Among these 73 people:

How long have people been on Fentanyl when they have Hyperreflexia? *

What is the gender of people who have Hyperreflexia when taking Fentanyl? *

female: 61.76 %
male: 38.24 %

What is the age of people who have Hyperreflexia when taking Fentanyl? *

What are other drugs people take besides Fentanyl? *

What are other side effects people have besides Hyperreflexia? *

Serotonin Syndrome (occurs when two drugs that affect the body's level of serotonin are taken together at the same time): 42 people, 57.53%
Agitation (state of anxiety or nervous excitement): 30 people, 41.10%
Clonus (series of involuntary, rhythmic, muscular contractions and relaxations): 24 people, 32.88%
Hypertonia (abnormal increase in muscle tension and a reduced ability of a muscle to stretch): 20 people, 27.40%
Fever: 18 people, 24.66%
Confusional State: 17 people, 23.29%
High Blood Pressure: 16 people, 21.92%
Arrhythmias (irregular heartbeat): 14 people, 19.18%
Nausea And Vomiting: 14 people, 19.18%
Tremor (trembling or shaking movements in one or more parts of your body): 12 people, 16.44%

What are the existing conditions these people have? *

Depression: 24 people, 32.88%
Anaesthesia: 13 people, 17.81%
Foetal Exposure During Pregnancy (exposing your unborn child to contraindicated in pregnancy leads birth defect): 9 people, 12.33%
General Anaesthesia: 9 people, 12.33%
Sedation: 4 people, 5.48%
Vasoplegia Syndrome (low systemic vascular resistance): 3 people, 4.11%
Stress And Anxiety: 3 people, 4.11%
Hypotonia (low muscle tone): 3 people, 4.11%
Multiple Sclerosis (a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath): 2 people, 2.74%
Anaesthesia Reversal: 2 people, 2.74%

* Approximation only. Some reports may have incomplete information.

Do you take Fentanyl and have Hyperreflexia?

- Check whether Hyperreflexia 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 Fentanyl:

Fentanyl (73,301 reports)

Hyperreflexia treatments and more:

Hyperreflexia (4,677 reports)

Browse all side effects of Fentanyl:

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 Hyperreflexia:

Hyperreflexia (422 drugs)

Browse all the conditions that are associated with Hyperreflexia:

Hyperreflexia (650 conditions)

How the study uses the data?

The study uses data from the FDA. It is based on fentanyl citrate (the active ingredients of Fentanyl) and Fentanyl (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.