In most cases, the shelf life of amoxicillin is between one and two years. Some factors that may affect the shelf life include exposure to light, heat, and moisture. Amoxicillin that comes in liquid form, which is also referred to as oral suspension amoxicillin, is typically required to be refrigerated. If the liquid amoxicillin is not refrigerated, this could negatively impact the shelf life. In general, the entire contents of a container of amoxicillin should be taken within 10 days after being prescribed depending on specific doctor instructions, and a person who is considering taking old amoxicillin should probably ask his doctor before doing so.
Most medicines, including amoxicillin, are labeled with expiration dates claiming the medicine is good for up to one year after being prescribed. It is possible that the majority of medicines are actually still safe to consume for more than a year after being prescribed, although they may not work as well as they did when they were fresh. The reduction in effectiveness is at least partly because of the likelihood that, within a year, most medicines have probably been exposed to unfavorable conditions that could impact how well they work. Exposure to light, heat, and moisture could, over time, cause the chemicals inside amoxicillin and other medicines not to react in the same way as they originally did, which means they might fail to be useful for treating various ailments.
A person who wants to ensure that his amoxicillin is safe to consume should follow all instructions on the container regarding storage for extended shelf life of amoxicillin. The ideal place for storing amoxicillin in tablet form to protect it from light, heat, or moisture is likely inside a medicine cabinet. Many people put containers of amoxicillin tablets in windowsills, but this usually leads to excess light and heat exposure. Storing amoxicillin in a bathroom out on a countertop rather than inside a medicine cabinet means the amoxicillin will likely come in contact with too much moisture. The shelf life of amoxicillin in liquid form may be slightly shorter than tablet amoxicillin because it normally has to be refrigerated, and the liquid form will likely not be effective for long if it is not kept refrigerated.
Regardless of its shelf life, it is important to keep in mind that amoxicillin is an antibiotic. Most doctors prescribe antibiotics to people with specific instructions to take it in its entirety to ensure that the infections the amoxicillin was prescribed to treat will go away. A person who failed to complete a round of amoxicillin and is thinking of taking what is left over to treat another infection should not do so without asking her doctor. If the amoxicillin is expired, it may not be as effective as it was when it was first prescribed. Amoxicillin that is not strong enough to kill an infection probably won't be useful, and the exposure to the weak amoxicillin might actually cause the bacteria inside the body to become stronger and harder to treat.