Use By Dates For Medicines: How Accurate Are They ?

[tim armstrong]

I've always looked at use by dates on packaged food, but only recently have I thought about the medicines I take regularly. A friend in the business tells me that the nearer the use by date the less effective medicines are as their half life expires. So you should always buy medicines that are in the first half of the expiry period to ensure their maximum effectiveness. It makes sense, but does this vary from drug to drug, or is there a general principle to observe.

A related issue - how do you tell the effectiveness of generic drugs ? I use diclofenac for rheumatism. As voltaren its quite expensive, but as volta, diffelene, bufenac forte and some others its quite cheap. Is it just trial and error to find a good and inexpensive version ? and do the generic drugs have shorter half lives ?

[Mobi]

Funny you should say that because the other day I purchased two bottles of eye drops for my glaucoma.

To their credit, they pointed out to me that one expired on 31st Aug, 2012 and the second on 30th Sept. As I use one per month, I decided they would be fine and bought them, though I did wonder why they hadn't had the decency reduced the price for nearly expired meds (TIT- I guess).

Unlike you, I had always thought that expiry dates - much like 'sell by dates' at supermarkets could be safely exceeded as the drug companies would build in a period of 'safety' past the expiry date, before the drug really did start to deteriorate.

Surely no drug company would market a drug that started to lose its effectiveness half way trhough its period of validity? Or would they?

[meatboy]

i myself take a lot of meds,always keep them in a fridge,i have seen pharmacists and hospitals put up presciptions[tabs]from large bottles maybe holding hundreds,one that comes to mind is ibuprofen they would empty into a small bottle then stick a label on the front.how did we manage before best by or use by dates.do they not ask for your out of date meds for say s.a.

so i would maybe not use out of date meds more than 1month.

[Sheryl]

The expiration date has nothing to do with half life. It is a period of time for which the manufacturer knows/guarantees the medication will remain potent and safe IF it was always stored properly. If at any point it was subjected to too much heat, direct sunlight etc then all best are off and I have n=known drugs tro be deactivated within a month that way.

If you know for a fact that the drug has always been properly stored then you can view the expiration date as a minimum guarantee and most drugs will be OK at least 1-2 years beyond that. But that is a big IF.

Be aware that certain drugs become dangerous when too old, this includes the various tetracyclines - do not take chances with them.

[lopburi3]

Funny you should say that because the other day I purchased two bottles of eye drops for my glaucoma.

To their credit, they pointed out to me that one expired on 31st Aug, 2012 and the second on 30th Sept. As I use one per month, I decided they would be fine and bought them, though I did wonder why they hadn't had the decency reduced the price for nearly expired meds (TIT- I guess).

Unlike you, I had always thought that expiry dates - much like 'sell by dates' at supermarkets could be safely exceeded as the drug companies would build in a period of 'safety' past the expiry date, before the drug really did start to deteriorate.

Surely no drug company would market a drug that started to lose its effectiveness half way trhough its period of validity? Or would they?

As I also take several glaucoma medications that clearly indicate requirements for storage under 25 deg would be especially careful buying any near expiration date here as do not trust most drug stores control. I know when I obtained from hospital they were taken from refrigerated storage and placed inside ice filled containers just for trip home. As the two drugs I take have a 3 year life they could have been in suspect storage for a very long time if anywhere near expiration date.

[Mobi]

Funny you should say that because the other day I purchased two bottles of eye drops for my glaucoma.

To their credit, they pointed out to me that one expired on 31st Aug, 2012 and the second on 30th Sept. As I use one per month, I decided they would be fine and bought them, though I did wonder why they hadn't had the decency reduced the price for nearly expired meds (TIT- I guess).

Unlike you, I had always thought that expiry dates - much like 'sell by dates' at supermarkets could be safely exceeded as the drug companies would build in a period of 'safety' past the expiry date, before the drug really did start to deteriorate.

Surely no drug company would market a drug that started to lose its effectiveness half way trhough its period of validity? Or would they?

As I also take several glaucoma medications that clearly indicate requirements for storage under 25 deg would be especially careful buying any near expiration date here as do not trust most drug stores control. I know when I obtained from hospital they were taken from refrigerated storage and placed inside ice filled containers just for trip home. As the two drugs I take have a 3 year life they could have been in suspect storage for a very long time if anywhere near expiration date.

I take Betoptic (Betaxolol 0.25%) eye drops which are never refrigerated but the pack says they should be stored under 25 deg, so I will be careful. I bought them at Fascino which is a large aircon modern pharmacy, but I hope their stock rooms are also cooled - if not, God help us all!

[tim armstrong]

Thanks for the interesting replies. I'm somewhat reassured that if you you look after the meds and keep them cool they will generally be ok.

[lopburi3]

Funny you should say that because the other day I purchased two bottles of eye drops for my glaucoma.

To their credit, they pointed out to me that one expired on 31st Aug, 2012 and the second on 30th Sept. As I use one per month, I decided they would be fine and bought them, though I did wonder why they hadn't had the decency reduced the price for nearly expired meds (TIT- I guess).

Unlike you, I had always thought that expiry dates - much like 'sell by dates' at supermarkets could be safely exceeded as the drug companies would build in a period of 'safety' past the expiry date, before the drug really did start to deteriorate.

Surely no drug company would market a drug that started to lose its effectiveness half way trhough its period of validity? Or would they?

As I also take several glaucoma medications that clearly indicate requirements for storage under 25 deg would be especially careful buying any near expiration date here as do not trust most drug stores control. I know when I obtained from hospital they were taken from refrigerated storage and placed inside ice filled containers just for trip home. As the two drugs I take have a 3 year life they could have been in suspect storage for a very long time if anywhere near expiration date.

I take Betoptic (Betaxolol 0.25%) eye drops which are never refrigerated but the pack says they should be stored under 25 deg, so I will be careful. I bought them at Fascino which is a large aircon modern pharmacy, but I hope their stock rooms are also cooled - if not, God help us all!

I visited new glaucoma doctor yesterday (who seems to be knowledgeable and has published writings here) and has changed me to a combination drug to avoid the 3 drops a day of previous treatment (have extremely dry eyes so less drops better) and she was very insistent to keep medicine in refrigeration at all times, only removing to use nightly and immediate return - so temp seems to be taken seriously. Expect low temps will also limit contamination issues. Your medication is clearly safe at refrigerator temps as listed as "Store upright at 2°- 25°C (36°- 77°F). Shake well before using." in quick Google. My medication is marked "Xalacom eye drops should be stored in a refrigerator at 2-8°C before opening. After opening the eye drops may kept outside of the fridge, but do not store them above 25°C. Keep the container in the outer carton in order to protect from light." Indeed it was packed in ice by hospital.