Efudex and Headache - a phase IV clinical study of FDA data

Summary:

Headache is reported as a side effect among people who take Efudex (fluorouracil), especially for people who are female, 60+ old, have been taking the drug for 1 - 6 months also take Synthroid, and have Crohn's disease.

The phase IV clinical study analyzes which people have Headache when taking Efudex. It is created by eHealthMe based on reports of 1,332 people who have side effects when taking Efudex from the FDA, and is updated regularly.

What is Efudex?

Efudex has active ingredients of fluorouracil. It is often used in actinic keratosis. eHealthMe is studying from 1,391 Efudex users. Check the latest studies of Efudex.

What is Headache?

Headache (pain in head) is found to be associated with 3,751 drugs and 5,772 conditions by eHealthMe. Check the latest studies of Headache.

On Jul, 18, 2026

1,332 people reported to have side effects when taking Efudex.
Among them, 54 people (4.05%) have Headache.

Among these 54 people:

How long have people been on Efudex when they have Headache? *

What is the gender of people who have Headache when taking Efudex? *

female: 61.9 %
male: 38.1 %

What is the age of people who have Headache when taking Efudex? *

What are other drugs people take besides Efudex? *

What are other side effects people have besides Headache? *

Fatigue (feeling of tiredness): 27 people, 50.00%
Pain: 22 people, 40.74%
Muscle Aches (muscle pain): 18 people, 33.33%
Weakness: 16 people, 29.63%
Joint Pain: 16 people, 29.63%
Chest Pain: 16 people, 29.63%
Rashes (redness): 14 people, 25.93%
Nausea (feeling of having an urge to vomit): 14 people, 25.93%
Depression: 13 people, 24.07%
Drowsiness: 12 people, 22.22%

What are the existing conditions these people have? *

Crohn's Disease (a condition that causes inflammation of the gastrointestinal tract): 16 people, 29.63%
Tuberculosis (a bacterial infection by mycobacterium tuberculosis): 8 people, 14.81%
Diverticulitis (digestive disease which involves the formation of pouches (diverticula) within the bowel wall): 7 people, 12.96%
Insomnia (sleeplessness): 5 people, 9.26%
Basal Cell Carcinoma (a skin cancer, it rarely metastasizes or kills): 4 people, 7.41%
Metastases To Bone (cancer spreads to bone): 4 people, 7.41%
Panic Disorder: 3 people, 5.56%
Drowsiness: 3 people, 5.56%
Essential Hypertension (primary hypertension): 3 people, 5.56%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 3 people, 5.56%

* Approximation only. Some reports may have incomplete information.

Do you take Efudex and have Headache?

- Check whether Headache 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 Efudex:

Efudex (1,391 reports)

Headache treatments and more:

Headache (756,642 reports)

Browse all side effects of Efudex:

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 Headache:

Headache (3,751 drugs)

Browse all the conditions that are associated with Headache:

Headache (5,772 conditions)

How the study uses the data?

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