Question
How long will treatment work after it expires?
25 September 2023. Related: Adherence, All topics.
How long after expiry dates can emitricitabin/tenofovir disproxil be taken. I have been taking an out of date batch for about a month as one of the packs had a different expiry date than the rest and was not noticed. Does it mean I am likely to get drug resistance as a result, all the other boxes are ok and will be used correctly. but am worried possible damage could already be done.
Answer
Hi, how are you?
No. This does not mean you are likely to get resistance.
Expired medication can still work.
Over time medicine, even in the packet will start to degrade. This means overtime the medication will work less well. Expiration is usually a date set when it is expected the drug will only work as well as 90% of what it did when it was made.
After the expiration date it does not mean the treatment wont work. Instead it means that it might be 89% effective as what it was when it was made.
As you had been taking it for a month, the treatment will still have worked. You have not risked resistance by it being out of date by a few weeks.
Josh.
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