How has your thyroxine been stored?

I've recently come across this study (link is to abstract, but full text is available), which describes how heat and humidity can have a negative impact on effectiveness of thyroid medication, specifically L-T4. I know it's a little late in the year to worry about that in the UK, but wonder how many pharmacies take this into account when dispensing medication which was manufactured months, even years, ago.

ncbi.nlm.nih.gov/pubmed/287...

8 Replies

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  • It's not just only patients that need to be instructed on proper modalities of LT4 storage. The dispensaries and pharmacies need to ensure proper storage before it even gets to the patient.

  • Sorry, perhaps I wasn't clear. I did say that I "wonder how many pharmacies take this into account when dispensing medication which was manufactured months, even years, ago". I agree completely that the onus is on them to make sure they are getting it right.

  • Remember light too can have an effect!

    AAH (who are, I think, the UK's largest distributor) are well aware and have a fleet of vehicles with temperature monitoring and control.

    Most pharmacies are churning over levothyroxine fast enough that they will only be stored on their premises for a moderate time. But I am concerned about this. I have a nasty imagination suggesting they switch off their air conditioning when they go home. Would very much hope they have a recording system which identifies any period outside the required range, though I doubt it.

  • It's the dispensaries I'm thinking of - attached to docs surgeries in rural areas - there is no pharmacist. The doctors act as the pharmacist/prescriber and the surgeries are closed at the weekend. I doubt there is any regulation of the temperature or light. In fact medicines are often dispensed under by a window and left sitting there. Do you think the blister packs and cardboard boxes are enough protection?

  • From light? Yes. One side of the blister is usually aluminium foil which is probably as near as possible 100% light-proof. But the other side usually looks fairly translucent. Within a card box, probably fine.

    The blisters are designed and intended to be fairly resistant to humidity changes.

    But temperature, yes, definitely a possible issue. Though remember that most information leaflets say something like 25 C - and even at that temperature they are supposed to last to their expiry date within tolerance for potency. If they leave them at higher temperatures (e.g. in the sun, or over a heater), not good.

  • Because I will only take Mercury Pharma levo, my rural doctor's dispensary hold it in bulk. I'm still receiving the 'old style' pills with the markings which were replaced in April 2016. They have obviously had these in stock at the dispensary for some time, and I have no way of knowing how they store them.

  • Maybe check the expiry date? Tricky with rural dispensaries, not much choice unless you're prepared and able to travel to a town.

  • Well, yes, obviously I have been keeping a very close eye on the expiry date.

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