According to federal law in the United States, prescription medications that are classified as controlled substances can only be transferred to another pharmacy one time over the phone. Controlled substances are medications that have the potential for abuse or dependence and are regulated by the Drug Enforcement Administration (DEA). Examples of controlled substances include opioids (such as oxycodone and hydrocodone), stimulants (such as amphetamine and methylphenidate), and benzodiazepines (such as diazepam and lorazepam). Non-controlled substances, on the other hand, do not have the same restrictions on transfer and can be transferred to another pharmacy as needed. It is important to note that laws regarding the transfer of prescription medications may vary by state and it is always best to consult with a healthcare professional or pharmacist for more information.