Final answer:
In the United States, pharmacies are required to keep records of controlled substances refill information for a minimum of 2 years.
Step-by-step explanation:
In the United States, the Drug Enforcement Administration (DEA) requires pharmacies to keep records of controlled substances refill information for a minimum of 2 years. This ensures compliance with federal regulations regarding controlled substances. These records typically include information such as patient data, prescriber information, and quantities dispensed. It's important for pharmacies to maintain accurate and up-to-date refill records to facilitate auditing and monitoring by regulatory agencies.