In 2009, the Danish Medicines Agency recorded a rise in the number of reported side effects (adverse reactions) from Eltroxin® after the manufacturer changed the excipients contained in Eltroxin®. We are still monitoring the development in adverse reactions reported for Eltroxin®.
Reports submitted from January 2009 to end-May 2010
From 1 January 2009 to 31 May 2010, the Danish Medicines Agency received a total of 1,114 side effect reports for Eltroxin®. The distribution per month is shown below.
80 % of the adverse reaction reports were submitted by the patients themselves or relatives, while physicians and other healthcare professionals accounted for 20 % of the reports.
Today, we primarily receive reports of adverse reactions that have been experienced before. About 15 % of the adverse reactions reported from January 2010 to end-May 2010 occurred in 2010.
Current status
We presume that the majority of the adverse reactions reported to the Danish Medicines Agency occurred in response to the reformulation of Eltroxin®, which in some patients has caused symptoms suggestive of overmedication or undermedication.
We estimate that the number of reports containing new adverse reactions will continue to decline.
We will continue to monitor the development in adverse reactions reported for Eltroxin®. Levothyroxine-containing products on the Danish market
Eltroxin® has for many years been the only levothyroxine-containing product sold in Denmark. On 28 December 2009, Euthyrox® entered the market in the strengths 25, 50 and 100 micrograms. Euthyrox® tablets have a scoreline so that they can be divided into two equal parts. You can find Danish summaries of product characteristics for Eltroxin® and Euthyrox® in the factbox to the right.
Precautionary measures to be taken by doctors
When patients switch between different levothyroxine-containing products or formulations, it is very important that a doctor monitors the level of thyroid stimulating hormone (TSH), in particular with respect to patients who experience side effects. However, due to the long half life of levothyroxine (approx. 7 days), the TSH level should not be measured until approx. 5-6 weeks after the patient has started taking the new product or the new formulation or has had the dose adjusted.
Side effects
The table below shows the ten most frequently reported suspected side effects in the period referred to above. These side effects are all suggestive of overmedication or undermedication with Eltroxin®.
Side effect |
Number of |
Sleepiness |
520 |
Headache |
422 |
Dizziness |
296 |
Nausea |
227 |
Disturbance in attention |
214 |
Weight increase |
210 |
Impaired memory |
186 |
Arthralgia |
175 |
Aching muscles |
174 |
Hair loss |
134 |
Please be aware that
Use the information cautiously
The information in the pharmacovigilance database does not reflect the risk of adverse reactions related to the individual medicines. Above all, the information is indicative of medicinal products that require increased attention and could give rise to further investigations.
An adverse reaction report is not the same as a true adverse reaction
An adverse reaction report contained in the pharmacovigilance database does not necessarily mean that there is a connection between the medicine and the adverse reaction. Adverse reactions are reported to and registered in the database, even if it is only suspected that there might be a connection between the medicine and the adverse reaction. Known side effects from Eltroxin® are listed in the summary of product characteristics, which you can find in the factbox to the right (in Danish only).
Previous status reports on Eltroxin® are also available in the factbox to the right.
Danish Medicines Agency, 2 July 2010
The Danish Medicines Agency’s pharmacovigilance database only contains side effects from Denmark.
Not all side effects are reported to the Danish Medicines Agency.
Information about the occurrence of side effects from a medicine should always be compared to the consumption of the medicine concerned. You can see the actual consumption in the Register of Medicinal Product Statistics at www.medstat.dk.
From 1 January 2009 to end-April 2010, 110,983 persons were treated with Eltroxin®.
