Synthroid and Immediate post-injection reaction - a phase IV clinical study of FDA data

Summary:

Immediate post-injection reaction is reported as a side effect among people who take Synthroid (levothyroxine sodium), especially for people who are female, 60+ old, also take Copaxone, and have Multiple sclerosis.

The phase IV clinical study analyzes which people have Immediate post-injection reaction 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 249,202 Synthroid users. Check the latest studies of Synthroid.

What is Immediate post-injection reaction?

Immediate post-injection reaction is found to be associated with 27 drugs and 112 conditions by eHealthMe. Check the latest studies of Immediate post-injection reaction.

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, 18, 2026

237,758 people reported to have side effects when taking Synthroid.
Among them, 13 people (0.01%) have Immediate post-injection reaction.

Could Synthroid cause Immediate post-injection reaction?

Among these 13 people:

What is the gender of people who have Immediate post-injection reaction when taking Synthroid? *

female: 100 %
male: 0.0 %

What is the age of people who have Immediate post-injection reaction when taking Synthroid? *

What are other drugs people take besides Synthroid? *

What are other side effects people have besides Immediate post-injection reaction? *

Dyspnea (difficult or laboured breathing): 7 people, 53.85%
Skin Blushing/flushing (a sudden reddening of the face, neck): 4 people, 30.77%
Itching: 3 people, 23.08%
Loss Of Consciousness: 3 people, 23.08%
Heart Palpitations (feelings or sensations that your heart is pounding or racing): 3 people, 23.08%
Weight Decreased: 3 people, 23.08%
Hypersensitivity: 3 people, 23.08%
Head Injury: 2 people, 15.38%
Headache (pain in head): 2 people, 15.38%
High Blood Cholesterol: 2 people, 15.38%

What are the existing conditions these people have? *

Multiple Sclerosis (a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath): 7 people, 53.85%
High Blood Pressure: 3 people, 23.08%
Osteoporosis (bones weak and more likely to break): 3 people, 23.08%
Type 2 Diabetes: 2 people, 15.38%
Migraine (headache): 2 people, 15.38%
Bladder Disorder: 1 person, 7.69%
Blood Potassium Decreased: 1 person, 7.69%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 1 person, 7.69%
High Blood Cholesterol: 1 person, 7.69%
Numbness And Tingling (unusual prickling sensations): 1 person, 7.69%

* Approximation only. Some reports may have incomplete information.

Do you take Synthroid and have Immediate post-injection reaction?

- Check whether Immediate post-injection reaction is associated with a drug or a condition
- Predict drug outcomes for up to one year with AI
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Related studies:

Effectiveness of, long term effects of, and alternative drugs to Synthroid:

Synthroid (249,202 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

Browse all the drugs that are associated with Immediate post-injection reaction:

Immediate post-injection reaction (27 drugs)

Browse all the conditions that are associated with Immediate post-injection reaction:

Immediate post-injection reaction (112 conditions)

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.