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ADR associated with change of the package of Thyrax® (levothyroxine) from a bottle to a blister

Date: 23 February 2015

In the autumn of 2014 Lareb detected a signal concerning ADRs of levothryroxine (brand name Thyrax®) which occurred after the a packaging change from a glass bottle to an aluminum blister. The majority of the ADRs concern symptoms associated with hyperthyroidism such as palpitations, hyperhidrosis and agitation. Levothyroxine is sensitive to environmental factors. It may be possible that the tablet in the bottle package, over time, contained a lower dose of levothyroxine compared to tablet in the blister package, due to environmental factors. This may explain the above described reactions.

Since raising the signal, the Medicines Evaluation Board has informed doctors, pharmacist and patients about this problem through a DHPC. There has also been attention in the national media. After a TV broadcast Lareb received more than 2.500 additional reports. In order to evaluate this signal further, Lareb is conducting additional research.

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