Zonisamide and On and off phenomenon - a phase IV clinical study of FDA data

Summary:

On and off phenomenon is reported as a side effect among people who take Zonisamide (zonisamide), especially for people who are male, 50-59 old, have been taking the drug for 1 - 6 months also take Clonazepam, and have Parkinson's disease.

The phase IV clinical study analyzes which people have On and off phenomenon when taking Zonisamide. It is created by eHealthMe based on reports of 11,045 people who have side effects when taking Zonisamide from the FDA, and is updated regularly.

What is Zonisamide?

Zonisamide has active ingredients of zonisamide. It is often used in epilepsy. eHealthMe is studying from 11,445 Zonisamide users. Check the latest studies of Zonisamide.

What is On and off phenomenon?

On and off phenomenon is found to be associated with 194 drugs and 182 conditions by eHealthMe. Check the latest studies of On and off phenomenon.

On Jul, 26, 2026

11,045 people reported to have side effects when taking Zonisamide.
Among them, 34 people (0.31%) have On and off phenomenon.

Could Zonisamide cause On and off phenomenon?

Among these 34 people:

How long have people been on Zonisamide when they have On and off phenomenon? *

What is the gender of people who have On and off phenomenon when taking Zonisamide? *

female: 35.29 %
male: 64.71 %

What is the age of people who have On and off phenomenon when taking Zonisamide? *

What are other drugs people take besides Zonisamide? *

What are other side effects people have besides On and off phenomenon? *

Hallucinations (sensations that appear real but are created by your mind): 12 people, 35.29%
Insomnia (sleeplessness): 10 people, 29.41%
Device Dislocation: 10 people, 29.41%
Malaise (a feeling of general discomfort or uneasiness): 7 people, 20.59%
Hypokinesia (decreased bodily movement): 7 people, 20.59%
Hallucination, Visual (seeing things that aren't there): 6 people, 17.65%
Delusion (a false belief or opinion): 6 people, 17.65%
Swallowing Difficulty: 5 people, 14.71%
Urticaria Chronic (long lasting rash of round, red welts on the skin that itch intensely): 5 people, 14.71%
Gait Disturbance: 5 people, 14.71%

What are the existing conditions these people have? *

Parkinson's Disease: 34 people, 100.00%
The Flu (the flu is caused by an influenza virus): 3 people, 8.82%
Dyskinesia (abnormality or impairment of voluntary movement): 3 people, 8.82%
Constipation: 3 people, 8.82%
Muscle Spasms (muscle contraction): 1 person, 2.94%
Freezing Phenomenon: 1 person, 2.94%

* Approximation only. Some reports may have incomplete information.

Do you take Zonisamide and have On and off phenomenon?

- Check whether On and off phenomenon 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 Zonisamide:

Zonisamide (11,445 reports)

Browse all side effects of Zonisamide:

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 On and off phenomenon:

On and off phenomenon (194 drugs)

Browse all the conditions that are associated with On and off phenomenon:

On and off phenomenon (182 conditions)

How the study uses the data?

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