The expiry date of a drug is one of the most important pieces of information that determines its safety. However, we should remember that in the case of many medicinal products, their shelf-life is significantly shortened when they are first opened.
Manufacturers are required to putthe expiry date of the drugboth on the outer packaging (cardboard box) and on the immediate packaging (blister, bottle). Pursuant to the Act, it must be expressed in an understandable and unencrypted manner, with the month and year.
Active and auxiliary substances contained in a medicinal product may decompose or undergo other chemical changes changing its effect.The expiry date of the drugrepresents the time during which the manufacturer guarantees that the composition and effect of the drug remain unchanged. This does not mean that the medicinal product will lose its properties immediately on the expiry of this period. However, it should be remembered that the use of medicinal products after this time is at your own risk.Expired drugscan be harmful, cause side effects and poisoning.
The expiry date of drugs that are already in use is a separate issue. Of course, in the case of tablets closed in blisters, opening the box and taking one of them does not affect the expiry date of the others. However, it is different in the case of the so-called large-dose packaging (tubes, bottles, jars and inhalers). When they are opened, the shelf life is shorter and depends on the type of preservatives and other protections used.
The analysis, which appeared in 2006 in the "Journal of Pharmaceutical Sciences", showed that in the case of 88 percent. medicines stored properly, the shelf life can be extended by at least one year.
Drug in the form of syrups
Information about the time in which such a drug should be used is placed on its packaging. Unfortunately, many people do not notice it. This problem very often concerns syrups for children. Preparations for fever or cough, partially used during a child's illness, are put "by the parents" "for later" in the home medicine cabinet. It happens that they are reused even after several months. And yet, by opening a bottle of syrup for the first time, we deprive it of sterility. From that moment on, microbes can penetrate into it, which will affect its durability. This process is added to slow down preservatives.
In addition, the sugar contained in syrups creates high osmotic pressure, which causes microorganisms to lose water, preventing the growth of most of them. However, there are microorganisms that can break down sucrose into simple sugars with the aid of an enzyme called invertase. As a result of their activity, the syrup becomes acidic. Some yeasts, on the other hand, have the ability to initiate alcoholic fermentation in syrups. Both processes deprive the drug of its properties and mean that taking such a drug may cause side effects - mainly on the part of the digestive system. If there is no other information on the medicine's packaging or in the package leaflet, it is assumed that the usability of the syrups from the first opening is 28 days. If the manufacturer has carried out additional tests, the shelf life may be longer.
There are syrups for fever or cough on the market that can be used up to 6 months after the first opening. This information must appear on the medicine packaging.
Suspensions, insulins …
Even more restrictive rules apply to antibiotics for children in the form of suspensions. They come in the form of a powder that parents themselves dissolve in a certain amount of water. The expiry date that can be found on the packaging of such an antibiotic is for the dry powder in intact condition. From the moment of preparing the suspension, it should be used within 5-14 days (depending on the drug). Very often it is then required to keep it in the refrigerator. The shortening of the expiry date of the drug may also result from the change in the temperature of its storage.
The best example of this are insulins. Stored in a refrigerator, they are valid as indicated on the package. However, after removing the ampoule from the refrigerator and loading it into the pen, it must be used within 30 days.
The expiry date may also be affected by light. Some medications come in the form of plastic, disposable ampoules packed several times in aluminum bags. After taking them out of such a pouch, the medicine, even in intact disposable containers, must be used within 3 months.
Watch out for eye drops
The vast majority of them should be used within 28 days of opening the bottle - regardless of the expiry date on the box. As in the case of syrups, it is related to the duration of the preservative action. Of course, there are exceptions to this rule. Many people are allergic to preservatives, so you can also buy drops without preservatives in pharmacies. This, of course, has an impact on their use-by date. Some drops without preservatives can be used for 7 days after opening them - however, there are few of them due to the uneconomic nature of such a solution. There are also eye drops available on the market in the so-called minimsach - for single use. Drops without preservatives in special bottles are also becoming more and more popular. Their uniqueness lies in the fact that they use patented mechanisms of extracting drops from the bottle, which prevent the penetration of microorganisms into its interior. The most popular systems of this type are ABAK and COMOD. In their case, despite the lack of preservatives, the drops can be used for several months.
"Zdrowie" monthly