Pegasys and Breast lump - a phase IV clinical study of FDA data

Summary:

Breast lump is reported as a side effect among people who take Pegasys (peginterferon alfa 2a), especially for people who are female, 50-59 old, have been taking the drug for 1 - 6 months also take Copegus, and have Fluid retention.

The phase IV clinical study analyzes which people have Breast lump when taking Pegasys. It is created by eHealthMe based on reports of 57,338 people who have side effects when taking Pegasys from the FDA, and is updated regularly.

What is Pegasys?

Pegasys has active ingredients of peginterferon alfa 2a. It is often used in hepatitis c. eHealthMe is studying from 57,446 Pegasys users. Check the latest studies of Pegasys.

What is Breast lump?

Breast lump (localized swelling that feels different from the surrounding breast tissue) is found to be associated with 786 drugs and 924 conditions by eHealthMe. Check the latest studies of Breast lump.

On Jul, 13, 2026

57,338 people reported to have side effects when taking Pegasys.
Among them, 63 people (0.11%) have Breast lump.

Among these 63 people:

How long have people been on Pegasys when they have Breast lump? *

What is the gender of people who have Breast lump when taking Pegasys? *

female: 87.3 %
male: 12.7 %

What is the age of people who have Breast lump when taking Pegasys? *

What are other drugs people take besides Pegasys? *

What are other side effects people have besides Breast lump? *

Fatigue (feeling of tiredness): 35 people, 55.56%
Cough: 25 people, 39.68%
Fever: 22 people, 34.92%
Anaemia (lack of blood): 22 people, 34.92%
Thrombocytopenia (decrease of platelets in blood): 20 people, 31.75%
Weight Decreased: 18 people, 28.57%
Weakness: 18 people, 28.57%
Pneumonia: 18 people, 28.57%
Hypotrichosis (a condition that affects hair growth): 15 people, 23.81%
Rashes (redness): 14 people, 22.22%

What are the existing conditions these people have? *

Fluid Retention (an abnormal accumulation of fluid in the blood): 2 people, 3.17%
Pain: 1 person, 1.59%
Inflammation: 1 person, 1.59%
Hypothyroidism (abnormally low activity of the thyroid gland, resulting in retardation of growth and mental development): 1 person, 1.59%
Enlarged Prostate: 1 person, 1.59%
Back Pain: 1 person, 1.59%
Agranulocytosis (a deficiency of granulocytes in the blood, causing increased vulnerability to infection): 1 person, 1.59%

* Approximation only. Some reports may have incomplete information.

Do you take Pegasys and have Breast lump?

- Check whether Breast lump 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 Pegasys:

Pegasys (57,446 reports)

Breast lump treatments and more:

Breast lump (9,236 reports)

Browse all side effects of Pegasys:

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 Breast lump:

Breast lump (786 drugs)

Browse all the conditions that are associated with Breast lump:

Breast lump (924 conditions)

How the study uses the data?

The study uses data from the FDA. It is based on peginterferon alfa 2a (the active ingredients of Pegasys) and Pegasys (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.