I'd be inclined to believe the expiration dates, for the most part. No harm in sniffing your drugs if you want to, but I wouldn't worry too much.
Expiration dating on drugs, at least in the US, is usually very conservative. The FDA is very particular about labelling of drugs, and in order to put a date like 2015 on the label the company has to have done a variety of studies to show stability for at least that long under various conditions. (Usually the actual expiration date is stepped back significantly from what they've shown stability for at typical room temperatures and humidities, in fact.)
Simply opening the bottle should not affect stability overly much by itself, and if it did, particularly since aspirin is an over-the-counter drug, the FDA would almost certainly require that to be stated on the label - that the expiration date is ONLY in unopened bottles. I haven't seen any aspirin labels like that, but I don't usually use all that much aspirin myself.
Opening the bottle *might* be a problem if you exposed the aspirin to very high temperatures and humidity - while 'dry' drugs often have very long stability, liquid forms almost never do, and heat and humidity will start to dissolve exposed surfaces of the aspirin tablets, so that would change things. It also would depend on what chemicals you exposed the aspirin to when you opened the bottle - airborne chemicals can react with a drug.
Mind, aspirin probably does merit particularly long expiration dates in part because the degradation products are not considered poisonous - we eat vinegar all the time and salicylic acid, while harder on the stomach than acetylsalicylic acid, was used for many years as a medication by itself. So what the companies and the FDA would be mostly concerned with would be potency or efficacy. But they'd still want a fairly high percentage of the main drug still present at the expiration date in order to allow the labelling like that.
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Date: 2006-05-05 05:46 am (UTC)Expiration dating on drugs, at least in the US, is usually very conservative. The FDA is very particular about labelling of drugs, and in order to put a date like 2015 on the label the company has to have done a variety of studies to show stability for at least that long under various conditions. (Usually the actual expiration date is stepped back significantly from what they've shown stability for at typical room temperatures and humidities, in fact.)
Simply opening the bottle should not affect stability overly much by itself, and if it did, particularly since aspirin is an over-the-counter drug, the FDA would almost certainly require that to be stated on the label - that the expiration date is ONLY in unopened bottles. I haven't seen any aspirin labels like that, but I don't usually use all that much aspirin myself.
Opening the bottle *might* be a problem if you exposed the aspirin to very high temperatures and humidity - while 'dry' drugs often have very long stability, liquid forms almost never do, and heat and humidity will start to dissolve exposed surfaces of the aspirin tablets, so that would change things. It also would depend on what chemicals you exposed the aspirin to when you opened the bottle - airborne chemicals can react with a drug.
Mind, aspirin probably does merit particularly long expiration dates in part because the degradation products are not considered poisonous - we eat vinegar all the time and salicylic acid, while harder on the stomach than acetylsalicylic acid, was used for many years as a medication by itself. So what the companies and the FDA would be mostly concerned with would be potency or efficacy. But they'd still want a fairly high percentage of the main drug still present at the expiration date in order to allow the labelling like that.