I picked up my prescription of Concerta 27mg last July. Is it still good to take now?

So the expiration date doesn't really indicate a point at which the medication is no longer effective or has become unsafe to use. Medical authorities state expired drugs are safe to take, even those that expired years ago. A rare exception to this may be tetracycline, but the report on this is controversial among researchers. It's true the effectiveness of a drug may decrease over time, but much of the original potency still remains even a decade after the expiration date. EXCLUDING nitroglycerin, insulin, and liquid antibiotics, most medications are as long-lasting as the ones tested by the military. Placing a medication in a cool place, such as a refrigerator, will help a drug remain potent for many years.

Is the expiration date a marketing ploy by drug manufacturers, to keep you restocking your medicine cabinet and their pockets regularly? You can look at it that way. Or you can also look at it this way: The expiration dates are very conservative to ensure you get everything you paid for. And, really, if a drug manufacturer had to do expiration-date testing for longer periods it would slow their ability to bring you new and improved formulations.
The next time you face the drug expiration date dilemma, consider what you've learned here. If the expiration date passed a few years ago and it's important that your drug is absolutely 100% effective, you might want to consider buying a new bottle. And if you have any questions about the safety or effectiveness of any drug, ask your pharmacist. He or she is a great resource when it comes to getting more information about your medications.
Info obtained from :
health.harvard.edu