This year we have had extended high temperatures which may well be concerning.
Most
medicines may be stored at temperature up to 25C, some allow up to 30C,
and some medicines have no storage conditions specified by the
manufacturer.
A single, isolated excursion of less than 5°C above
the specified maximum storage temperature for less than 7 days is
unlikely to have an adverse effect on the medicines.
More comprehensive guidance, though intended for pharmacies rather than patients, is available here:
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| Screenshot of SPS webpage |
Understanding why temperature management is important for medicines storage
Published 10 November 2022 · Last updated 5 January 2023
Domestic Refrigerators
Most domestic refrigerators have relatively poor temperature control. This might well be perfectly adequate for safe food storage.
In particular, refrigerators which self-defrost often actually warm up as part of the defrost cycle. And many of these refrigerators will switch into an extra-powerful chilling mode in order to restore the temperature.
However, even domestic refrigerators without self-defrost can have significant swings of temperature.
Location within the refrigerator also has a major effect.
In general, large items, bottles or cartons of liquid, whole vegetables, blocks of butter, will barely change temperature. So you might never notice any problems. But small items, like a few tablets, can easily change up or down to a much greater extent.
Freezing
If tablets approach freezing point, all sorts of things happen to any water they contain. (Bear in mind, levothyroxine tablets actually contain levothyroxine sodium mostly in its pentahydrate form. That is, five molecules of water loosely connected to each molecule of levothyroxine sodium.) The water can move round and form condensation, even crystals of ice.
I imagine we have all seen frozen foods where the container is lined by ice crystals? And the food itself has become somewhat dry? That sort of change can occur in tablets.
The impact of these changes is difficult to assess. It could affect how well tablets split, or disintegrate and disperse. And how sensitive the tablets are to oxygen and light.
I started by saying "approach freezing point" because these issues start to occur well before reaching 0 C. Probably unsatisfactory if they ever reach 5 C. 10 C would be much safer.
The above issues can occur even if the tablets are perfectly sealed.
Condensation
If anything it taken from a cold place into a warmer environment, especially if it is humid, condensation can form. This can cause severe deterioration of tablets - physical, chemical and biological.
Some moulds and bacteria can readily grow in a fine damp layer of condensation.
For that reason, always leave any chilled medicines sealed until they have reached ambient temperature. Allow them tio very slowly warm up over many hours.
Safest Refrigeration
All that is needed is to avoid the temperature rising above the safe storage maximum. Some of us have cellars, or larders, though both are all too rare these days.
Another possibility is a wine storage unit - which is not intended to chill its contents, just keep the wine at an even temperature.
If you wish to link to this page on HealthUnlocked, copy the entire dark red text below and paste into a post or reply:
[i][b]helvella - Storing Medicines: Official Advice[/b]
A brief introduction to storing medicines and onward link to official advice.
Last updated 10/02/2015[/i]
Link to blog:
https://helvella.blogspot.com/p/helvella-storing-medicines-official.html
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