# \[e-drug\] Expiry dates of drugs **URL:** \ **Category:** e-drug\ **Created:** [March 31, 2003, 11:59am UTC](https://talk.edrugplus.org/t/e-drug-expiry-dates-of-drugs/16475 "2003-03-31T11:59:59Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![karin](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@karin](https://talk.edrugplus.org/u/karin)\ **Post date:** [March 31, 2003, 11:59am UTC](https://talk.edrugplus.org/t/e-drug-expiry-dates-of-drugs/16475/1 "2003-03-31T11:59:59Z")
E-drug: Expiry dates of drugs ------------------------------------------------------------------------- Dear Dr Srinivas, A major factor determining expiry dates is related to how long the manufacturer wants to carry on the stability tests. These tests are time consuming and can therefore be expensive... So often a manufacturer decides, after x months, that it has been enough. If at that time (i.e. after x months) the product is still in good enough shape, the manufacturer will use "x months" as shelf life (how many months after "x" the product would still be OK is not of major interest to the manufacturer). The value of "x" however is often quite arbitrary and may vary between manufacturers (hence the variation between similar products from different manufacturers). Having said that, in a number of cases (i.e. with 'critical or sensitive products') the indicated expiry date really does indicate that the product is not suitable for use any more after that date (though storage conditions usually have more influence than time per se). Then, different inactive ingredients can also have an influence on expiry dates - though I don't think there are many general rules here. But esp. for tablets, the 1st reason I mentioned is much more frequently the actual factor determining expiry date than most people realize. Hope this is useful. Karin Timmermans WHO Indonesia Email: Karin@who.or.id -- To send a message to E-Drug, write to: e-drug@usa.healthnet.org To subscribe or unsubscribe, write to: majordomo@usa.healthnet.org in the body of the message type: subscribe e-drug OR unsubscribe e-drug To contact a person, send a message to: e-drug-help@usa.healthnet.org Information and archives: [http://www.essentialdrugs.org/edrug](http://www.essentialdrugs.org/edrug)