Zyrtec and Large intestinal ulcer - a phase IV clinical study of FDA data

Summary:

Large intestinal ulcer is reported as a side effect among people who take Zyrtec (cetirizine hydrochloride), especially for people who are female, 50-59 old, also take Synthroid, and have Irritable bowel syndrome.

The phase IV clinical study analyzes which people have Large intestinal ulcer when taking Zyrtec. It is created by eHealthMe based on reports of 109,528 people who have side effects when taking Zyrtec from the FDA, and is updated regularly.

What is Zyrtec?

Zyrtec has active ingredients of cetirizine hydrochloride. It is often used in allergies. eHealthMe is studying from 114,619 Zyrtec users. Check the latest studies of Zyrtec.

What is Large intestinal ulcer?

Large intestinal ulcer is found to be associated with 392 drugs and 514 conditions by eHealthMe. Check the latest studies of Large intestinal ulcer.

On Jul, 13, 2026

109,528 people reported to have side effects when taking Zyrtec.
Among them, 20 people (0.02%) have Large intestinal ulcer.

Could Zyrtec cause Large intestinal ulcer?

Among these 20 people:

What is the gender of people who have Large intestinal ulcer when taking Zyrtec? *

female: 80 %
male: 20 %

What is the age of people who have Large intestinal ulcer when taking Zyrtec? *

What are other drugs people take besides Zyrtec? *

What are other side effects people have besides Large intestinal ulcer? *

Fever: 6 people, 30.00%
Abdominal Pain: 5 people, 25.00%
Diarrhea: 5 people, 25.00%
Chronic Obstructive Pulmonary Disease (a progressive disease that makes it hard to breathe): 4 people, 20.00%
Pneumonia: 4 people, 20.00%
Gastrointestinal Disorder (functional problems of gastrointestinal tract): 4 people, 20.00%
Gastrointestinal Necrosis (destruction of gastrointestinal organ): 4 people, 20.00%
Weight Increased: 3 people, 15.00%
Ascites (accumulation of fluid in the abdominal cavity): 3 people, 15.00%
Lower Gastrointestinal Haemorrhage (bleeding in the large intestine, rectum, or anus is called lower gi bleeding): 3 people, 15.00%

What are the existing conditions these people have? *

Hypothyroidism (abnormally low activity of the thyroid gland, resulting in retardation of growth and mental development): 7 people, 35.00%
Irritable Bowel Syndrome: 7 people, 35.00%
Rheumatoid Arthritis (a chronic progressive disease causing inflammation in the joints): 5 people, 25.00%
Chronic Obstructive Pulmonary Disease (a progressive disease that makes it hard to breathe): 4 people, 20.00%
Retinal Vessel Occlusion (a blockage in one of the small arteries): 3 people, 15.00%
Parkinson's Disease: 3 people, 15.00%
Pain: 3 people, 15.00%
Osteoporosis (bones weak and more likely to break): 3 people, 15.00%
Constipation: 3 people, 15.00%
Sleep Disorder: 3 people, 15.00%

* Approximation only. Some reports may have incomplete information.

Do you take Zyrtec and have Large intestinal ulcer?

- Check whether Large intestinal ulcer 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 Zyrtec:

Zyrtec (114,619 reports)

Browse all side effects of Zyrtec:

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 Large intestinal ulcer:

Large intestinal ulcer (392 drugs)

Browse all the conditions that are associated with Large intestinal ulcer:

Large intestinal ulcer (514 conditions)

How the study uses the data?

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