How long after the expiration date is Lexapro still effective?

Once a medication expires, there is no guarantee of potency of that medication. The manufacturer has set the expiration date listed because they have determined that the medication will not have biologically degraded (if stored properly) prior to that date. After that, it is likely that the drug will begin to naturally break down. Degredation rate will likely be increased if stored for any period of time in warm, light, and/or wet environments. It is best to talk to a physican about getting a new prescription for your medication or having another medication prescribed if finances are an issue. Conditions such as anxiety/depression will be inadequately treated if your medication has not maintained its potency, and this could lead to very undesirable side effects for you.