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Lamictal xr vs. Synthroid: side effect and effectiveness comparison (a real world drug study)

Summary:

We compare the side effects and drug effectiveness of Lamictal xr and Synthroid. The phase IV clinical study is created by eHealthMe based on reports (from sources including the FDA) of 775,881 people who take Lamictal xr and Synthroid, and is updated regularly.

What is Lamictal xr?

Lamictal xr has active ingredients of lamotrigine. It is often used in epilepsy. eHealthMe is studying from 1,853 Lamictal xr users. Check the latest studies of Lamictal xr.

What is Synthroid?

Synthroid has active ingredients of levothyroxine sodium. It is often used in hypothyroidism. eHealthMe is studying from 249,198 Synthroid users. Check the latest studies of Synthroid.

On Jul, 09, 2026

775,881 people who take Lamictal xr and Synthroid are studied.

Lamictal xr vs Synthroid drug comparison reports.

Drugs being compared in this study:

  • Synthroid (levothyroxine sodium)
  • Lamictal Xr (lamotrigine)

Most common side effects of the drugs, overall:

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Most common side effects of the drugs, in long term (1+ years) use:

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Drug effectiveness:

Lamictal Xr:

  • not at all: 3.27 %
  • somewhat: 16.88 %
  • moderate: 30.95 %
  • high: 32.19 %
  • very high: 16.71 %

Synthroid:

  • not at all: 2.36 %
  • somewhat: 13.74 %
  • moderate: 29.1 %
  • high: 36.18 %
  • very high: 18.62 %

Want to compare Lamictal xr with Synthroid?

- Personalize this study to your gender and age (0-99+)

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.

Related publications that referenced our studies

Related studies

Alternative drugs to, pros and cons of:

Browse all side effects of Lamictal xr:

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 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

How the study uses the data?

The study is based on lamotrigine and levothyroxine sodium (the active ingredients of Lamictal xr and Synthroid, respectively). Other drugs that have the same active ingredients (e.g. generic drugs or brand names) are also considered. Dosage of drugs is not considered in the study.

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.

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