Synthroid and Sinus node dysfunction - a phase IV clinical study of FDA data

Summary:

Sinus node dysfunction is reported as a side effect among people who take Synthroid (levothyroxine sodium), especially for people who are female, 60+ old, have been taking the drug for 5 - 10 years also take Lasix, and have Osteoporosis.

The phase IV clinical study analyzes which people have Sinus node dysfunction when taking Synthroid. It is created by eHealthMe based on reports of 237,758 people who have side effects when taking Synthroid from the FDA, and is updated regularly.

What is Synthroid?

Synthroid has active ingredients of levothyroxine sodium. It is often used in hypothyroidism. eHealthMe is studying from 249,168 Synthroid users. Check the latest studies of Synthroid.

What is Sinus node dysfunction?

Sinus node dysfunction (a group of abnormal heart rhythms) is found to be associated with 1,265 drugs and 834 conditions by eHealthMe. Check the latest studies of Sinus node dysfunction.

On Aug, 24, 2025

237,758 people reported to have side effects when taking Synthroid.
Among them, 138 people (0.06%) have Sinus node dysfunction.

Could Synthroid cause Sinus node dysfunction?

Among these 138 people:

How long have people been on Synthroid when they have Sinus node dysfunction? *

What is the gender of people who have Sinus node dysfunction when taking Synthroid? *

female: 72.06 %
male: 27.94 %

What is the age of people who have Sinus node dysfunction when taking Synthroid? *

What are other drugs people take besides Synthroid? *

What are other side effects people have besides Sinus node dysfunction? *

Atrial Fibrillation/flutter (atrial fibrillation and flutter are abnormal heart rhythms in which the atria, or upper chambers of the heart, are out of sync with the ventricles): 72 people, 52.17%
High Blood Pressure: 47 people, 34.06%
Dyspnea (difficult or laboured breathing): 42 people, 30.43%
Dizziness: 41 people, 29.71%
Cardiac Failure Congestive: 40 people, 28.99%
Hypotension (abnormally low blood pressure): 37 people, 26.81%
Heart Attack: 35 people, 25.36%
Pneumonia: 35 people, 25.36%
Weakness: 34 people, 24.64%
Anaemia (lack of blood): 34 people, 24.64%

What are the existing conditions these people have? *

Pain: 17 people, 12.32%
Osteoporosis (bones weak and more likely to break): 17 people, 12.32%
High Blood Pressure: 16 people, 11.59%
Multiple Myeloma (cancer of the plasma cells): 11 people, 7.97%
High Blood Cholesterol: 10 people, 7.25%
Depression: 10 people, 7.25%
Atrial Fibrillation/flutter (atrial fibrillation and flutter are abnormal heart rhythms in which the atria, or upper chambers of the heart, are out of sync with the ventricles): 10 people, 7.25%
Osteopenia (a condition where bone mineral density is lower than normal): 9 people, 6.52%
Musculoskeletal Chest Pain (pain in chest muscle or nerve or bones): 9 people, 6.52%
Paget's Disease (disorder that involves abnormal bone destruction and regrowth, which results in deformity): 9 people, 6.52%

* Approximation only. Some reports may have incomplete information.

Do you take Synthroid and have Sinus node dysfunction?

- Check whether Sinus node dysfunction 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 Synthroid:

Synthroid (249,168 reports)

Browse all side effects of Synthroid:

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

Common drugs associated with Sinus node dysfunction:

Browse all the drugs that are associated with Sinus node dysfunction:

Sinus node dysfunction (1,265 drugs)

Common conditions associated with Sinus node dysfunction:

Hypertension: 487 reports
Blood pressure increased: 483 reports
Atrial fibrillation: 337 reports
Diabetes mellitus aggravated: 222 reports
Diabetes: 221 reports
Multiple myeloma: 169 reports
Osteoporosis: 163 reports
Thin bones: 153 reports
Rheumatoid arthritis: 124 reports

Browse all the conditions that are associated with Sinus node dysfunction:

Sinus node dysfunction (834 conditions)

Drugs similar to Synthroid and Sinus node dysfunction :

How the study uses the data?

The study uses data from the FDA. It is based on levothyroxine sodium (the active ingredients of Synthroid) and Synthroid (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.