Final answer:
In emergency situations, a prescription for Schedule II controlled substances may be called into a pharmacy, with the requirement that a written prescription must follow within 7 days according to DEA regulations in the United States.
Step-by-step explanation:
In emergency situations, a prescription for a Schedule II controlled substance can indeed be telephoned to the pharmacy; however, the prescriber is responsible for providing a written prescription to the pharmacy within a certain time frame. The specific time frame can vary depending on the country's regulations or specific state laws where the prescriber and the pharmacy are located. In the United States, for instance, the prescriber must follow up with a written prescription sent to the pharmacy within 7 days after the emergency oral prescription was made, as per the Drug Enforcement Administration (DEA) regulations. This requirement helps to maintain controlled substance regulations while also allowing for the necessary flexibility in true emergencies where immediate treatment is paramount and the patient cannot wait for a written prescription.