# How long can Rx drugs last? **URL:** \ **Category:** Factual Questions\ **Created:** [September 12, 2002, 5:27pm UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133 "2002-09-12T17:27:13Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Second](https://avatars.discourse-cdn.com/v4/letter/s/9e8a1a/32.png) [@Second](https://boards.straightdope.com/u/Second)\ **Post date:** [September 12, 2002, 5:27pm UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/1 "2002-09-12T17:27:13Z")
I just came back from the dentist, tooth extraction, and I still live at home w/ my grandmother. Anyway I am in some pain, She used to get prescribed Merpozine, which looking on the net is meperidine (opiate analgesic) & promethazine (phenergan - anti-nausea (i think)). But these pills are from 1996. And I’m very very tempted to take one, but I want to make sure they don’t go “bad” per say. They have been in the a normal pill bottle all this time and away from direct sunlight. So what’s the shelf life?? ---
**Author:** ![Yeah](https://avatars.discourse-cdn.com/v4/letter/y/dbc845/32.png) [@Yeah](https://boards.straightdope.com/u/Yeah)\ **Post date:** [September 13, 2002, 12:48am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/2 "2002-09-13T00:48:47Z")
[http://www.medletter.com/freedocs/expdrugs.pdf](http://www.medletter.com/freedocs/expdrugs.pdf) or [http://www.medletter.com/html/prm.htm#ExpDrugs](http://www.medletter.com/html/prm.htm#ExpDrugs) and click on Drugs Past Their Expiration Date ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [September 13, 2002, 1:35am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/3 "2002-09-13T01:35:29Z")
One danger of using the drug past the date (I think 3-5 years is about the limit in most cases) is that the active ingredient may degrade over time, creating nasty secondary compounds that can make you ill or worse. Excipients (non-actives) may also degrade, possibly yielding the same result. I know where I worked this summer. we ended a stability protocol on a project that had lasted 3 years - that was as long as it was necessary to test it for, and I don’t know if any data is available to see if it still falls within the norms after that point. I wouldn’t recommend you take her meds, not only because they might be old, but also because they were not prescribed for you. If you are taking any other meds, or have a particular physical condition (which you might not yet know about, but a doctor could find) etc, then the effects of the drugs might be disastrous. Go to the pharmacy and obtain an OTC painkiller, after having talked to the pharmacist first! ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [September 13, 2002, 1:42am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/4 "2002-09-13T01:42:42Z")
One danger of using the drug past the date (I think 3-5 years is about the limit in most cases) is that the active ingredient may degrade over time, creating nasty secondary compounds that can make you ill or worse. Excipients (non-actives) may also degrade, possibly yielding the same result. I know where I worked this summer. we ended a stability protocol on a project that had lasted 3 years - that was as long as it was necessary to test it for, and I don’t know if any data is available to see if it still falls within the norms after that point. I wouldn’t recommend you take her meds, not only because they might be old, but also because they were not prescribed for you. If you are taking any other meds, or have a particular physical condition (which you might not yet know about, but a doctor could find) etc, then the effects of the drugs might be disastrous. Go to the pharmacy and obtain an OTC painkiller, after having talked to the pharmacist first! ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [September 13, 2002, 1:47am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/5 "2002-09-13T01:47:56Z")
One danger of using the drug past the date (I think 3-5 years is about the limit in most cases) is that the active ingredient may degrade over time, creating nasty secondary compounds that can make you ill or worse. Excipients (non-actives) may also degrade, possibly yielding the same result. I know where I worked this summer. we ended a stability protocol on a project that had lasted 3 years - that was as long as it was necessary to test it for, and I don’t know if any data is available to see if it still falls within the norms after that point. I wouldn’t recommend you take her meds, not only because they might be old, but also because they were not prescribed for you. If you are taking any other meds, or have a particular physical condition (which you might not yet know about, but a doctor could find) etc, then the effects of the drugs might be disastrous. Go to the pharmacy and obtain an OTC painkiller, after having talked to the pharmacist first! ---
**Author:** ![miatachris](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@miatachris](https://boards.straightdope.com/u/miatachris)\ **Post date:** [September 13, 2002, 2:18am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/6 "2002-09-13T02:18:15Z")
It’s likely that the meds in question are simply inactive. The only meds that degrade into a harmful substance are tetracycline. Remember that federal law prohibits transfer of rx drugs to others than for whom prescribed. ---
**Author:** ![miatachris](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@miatachris](https://boards.straightdope.com/u/miatachris)\ **Post date:** [September 13, 2002, 2:26am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/7 "2002-09-13T02:26:15Z")
It’s likely that the meds in question are simply inactive. The only meds that degrade into a harmful substance are tetracycline. Remember that federal law prohibits transfer of rx drugs to others than for whom prescribed. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [September 13, 2002, 2:36am UTC](https://boards.straightdope.com/t/how-long-can-rx-drugs-last/128133/8 "2002-09-13T02:36:34Z")
As **miatachris** points out, taking prescription medications not prescribed to you is illegal. We do not countenance discussions that will facilitate your breaking the law. This thread is closed. bibliophage moderator GQ