Every drug, every drug product, every medication sold over-the-counter, as well as on prescription, has an expiry date. This date is imprinted on the packaging, generally right on the medication container. This expiry is the date before which the medication will have the stated strength, will provide the desired benefits and does this safely. Manufacturers will perform stability testing on their products measuring potency and stability over time. The expiry date is established as a result of this testing, and is specific to every drug, every dosage form (tablet, capsule, liquid, etc.), under normal usage conditions. For some drugs, using the product after the expiry date can expose the individual to harmful by products of the medication's break down
The rule is, only use medication that has not exceeded its expiry date, disposing of expired drugs properly.