Liothyronine 20 microgram tablets: continuity of supply and potential need for patient monitoring

Recent interruption to the supply of liothyronine 20 microgram tablets from Amdipharm Mercury.

Article date: May 2013

There has been a recent interruption to the supply of liothyronine 20 microgram tablets from Amdipharm Mercury.

As a result of this current unavailability, patients taking this medicine may have had their prescription filled by an unlicensed product (imported from the EU) under the direct personal responsibility of a prescriber. The interchangeability of Amdipharm Mercury liothyronine tablets with liothyronine tablets that are not currently licensed in the UK cannot be assured because they may not be bioequivalent.

Advice for healthcare professionals and patients:

  • prescribers should be alert to the possibility that a change in a patient’s symptoms and thyroid-stimulating hormone (TSH) status may be attributed to switching between liothyronine 20 microgram tablets from Amdipharm Mercury and another product
  • patients who experience a significant change in symptoms should have their TSH status reviewed and their dose of liothyronine adjusted accordingly
  • the following patients may be particularly susceptible to changes in bioavailability of liothyronine and may require particularly close monitoring:
    • pregnant women, throughout pregnancy but especially in the first trimester
    • those with heart disease
    • these patients who have been prescribed an alternative, unlicensed product should be contacted and given an early appointment for a clinical review and blood test
  • in the small number of patients prescribed liothyronine long term (usually in combination with levothyroxine), thyroid function tests should be repeated 1 to 2 months after any change in preparation to ensure the target TSH has been maintained

Further information

See message sent via the Central Alerting System May 21, 2013

See also MHRA website

Article citation: Drug Safety Update May 2013 vol 6, issue 10: S1.

Published 11 December 2014