Valacyclovir and Fistula - a phase IV clinical study of FDA data

Summary:

Fistula is reported as a side effect among people who take Valacyclovir (valacyclovir hydrochloride), especially for people who are female, 40-49 old, have been taking the drug for 1 - 6 months also take Prednisone, and have Crohn's disease.

The phase IV clinical study analyzes which people have Fistula when taking Valacyclovir. It is created by eHealthMe based on reports of 41,259 people who have side effects when taking Valacyclovir from the FDA, and is updated regularly.

What is Valacyclovir?

Valacyclovir has active ingredients of valacyclovir hydrochloride. It is often used in genital herpes. eHealthMe is studying from 42,107 Valacyclovir users. Check the latest studies of Valacyclovir.

What is Fistula?

Fistula (an abnormal connection or passageway between two) is found to be associated with 842 drugs and 906 conditions by eHealthMe. Check the latest studies of Fistula.

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 Aug, 26, 2026

41,259 people reported to have side effects when taking Valacyclovir.
Among them, 14 people (0.03%) have Fistula.

Among these 14 people:

How long have people been on Valacyclovir when they have Fistula? *

What is the gender of people who have Fistula when taking Valacyclovir? *

female: 75 %
male: 25 %

What is the age of people who have Fistula when taking Valacyclovir? *

What are other drugs people take besides Valacyclovir? *

What are other side effects people have besides Fistula? *

Canker Sores (painful, open sore in the mouth): 4 people, 28.57%
Nausea (feeling of having an urge to vomit): 3 people, 21.43%
Wound: 3 people, 21.43%
Infection: 3 people, 21.43%
Oral Herpes (viral infection of mouth): 3 people, 21.43%
Appendicitis (inflammation of the appendix): 3 people, 21.43%
Psoriasis (immune-mediated disease that affects the skin): 2 people, 14.29%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 2 people, 14.29%
Haemoglobin Decreased: 2 people, 14.29%
Fatigue (feeling of tiredness): 2 people, 14.29%

What are the existing conditions these people have? *

Crohn's Disease (a condition that causes inflammation of the gastrointestinal tract): 5 people, 35.71%
Ulcerative Colitis (inflammatory bowel disease (ibd). it causes swelling, ulcerations, and loss of function of the large intestine): 3 people, 21.43%
Pain: 3 people, 21.43%
Muscle Spasms (muscle contraction): 3 people, 21.43%
Headache (pain in head): 1 person, 7.14%
Blood Sodium Abnormal: 1 person, 7.14%
Depression: 1 person, 7.14%
Diabetes: 1 person, 7.14%
Diarrhea: 1 person, 7.14%
Folate Deficiency (lack of folic acid): 1 person, 7.14%

* Approximation only. Some reports may have incomplete information.

Do you take Valacyclovir and have Fistula?

- Check whether Fistula 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 Valacyclovir:

Valacyclovir (42,107 reports)

Fistula treatments and more:

Fistula (16,274 reports)

Browse all side effects of Valacyclovir:

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 Fistula:

Fistula (842 drugs)

Browse all the conditions that are associated with Fistula:

Fistula (906 conditions)

How the study uses the data?

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