Can an issued DEA number for a physician be used in another state?

Yes, a physician's DEA number can be used in another state as long as they are registered with the DEA and have the appropriate state licensure for that state. However, individual states may have their own regulations regarding the prescription of controlled substances, so it's important for physicians to be aware of and comply with those state-specific laws. Additionally, if the physician is practicing in a different state, they may need to apply for a state-controlled substance registration.