Zyrtec and Metamorphopsia - a phase IV clinical study of FDA data

Summary:

Metamorphopsia is reported as a side effect among people who take Zyrtec (cetirizine hydrochloride), especially for people who are female, 60+ old, also take Lucentis, and have Diabetic retinal oedema.

The phase IV clinical study analyzes which people have Metamorphopsia 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 114,620 Zyrtec users. Check the latest studies of Zyrtec.

What is Metamorphopsia?

Metamorphopsia (a type of distorted vision in which a grid of straight lines appears wavy and parts of the grid may appear blank) is found to be associated with 209 drugs and 368 conditions by eHealthMe. Check the latest studies of Metamorphopsia.

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, 14, 2026

109,528 people reported to have side effects when taking Zyrtec.
Among them, 16 people (0.01%) have Metamorphopsia.

Among these 16 people:

What is the gender of people who have Metamorphopsia when taking Zyrtec? *

female: 62.5 %
male: 37.5 %

What is the age of people who have Metamorphopsia when taking Zyrtec? *

What are other drugs people take besides Zyrtec? *

What are other side effects people have besides Metamorphopsia? *

Visual Impairment: 8 people, 50.00%
Malaise (a feeling of general discomfort or uneasiness): 6 people, 37.50%
Vision Blurred: 6 people, 37.50%
Cystoid Macular Oedema (fluid accumulation after cataract surgery): 4 people, 25.00%
Visual Acuity Reduced (reduced clearness of vision): 4 people, 25.00%
Movement Disorder (neurological syndromes where they may be excess of movement or a paucity of movement that is not connected to weakness): 4 people, 25.00%
Memory Loss: 4 people, 25.00%
Dizziness: 4 people, 25.00%
Fibromyalgia (a long-term condition which causes pain all over the body): 3 people, 18.75%
Paraesthesia (sensation of tingling, tickling, prickling, pricking, or burning of a person's skin with no apparent long-term physical effect): 3 people, 18.75%

What are the existing conditions these people have? *

Diabetic Retinal Oedema (excessive build-up of fluid in the retina due to diabetes): 4 people, 25.00%
High Blood Pressure: 3 people, 18.75%
Retinal Vessel Occlusion (a blockage in one of the small arteries): 2 people, 12.50%
Retinal Oedema (swelling of retina): 2 people, 12.50%
Breast Cancer Metastatic: 2 people, 12.50%
Diabetic Retinopathy (damage to the retina caused by complications of diabetes): 2 people, 12.50%
Hypersensitivity: 2 people, 12.50%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 1 person, 6.25%
Colitis Microscopic (inflammation of colon with diarrhoea and abdominal cramps): 1 person, 6.25%
Eczema (patches of skin become rough and inflamed, with itching and bleeding blisters): 1 person, 6.25%

* Approximation only. Some reports may have incomplete information.

Do you take Zyrtec and have Metamorphopsia?

- Check whether Metamorphopsia 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 (114,620 reports)

Metamorphopsia treatments and more:

Metamorphopsia (2,072 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 Metamorphopsia:

Metamorphopsia (209 drugs)

Browse all the conditions that are associated with Metamorphopsia:

Metamorphopsia (368 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.