What is NOT required on a written prescription for Schedule III-V controlled substances?

The correct answer is that the patient's phone number is not required on a written prescription for Schedule III-V controlled substances. When it comes to prescriptions for controlled substances, the regulations focus on key pieces of information necessary for the identification of the patient, the prescriber, and the medication prescribed.

The prescriber's profession is important to include because it ensures that the individual prescribing the medication is authorized to do so. This could include a physician, dentist, or another qualified healthcare professional, as regulations can vary based on their specific scope of practice.

The patient's age is also relevant, particularly in ensuring that medications are appropriately prescribed for the age group of the patient, which might influence dosage or safety considerations. Including the patient's age helps pharmacists confirm that the medication is appropriate for the patient’s demographic.

The drug strength is another critical requirement as it specifies the exact dosage prescribed, which can be essential for effective treatment and avoiding potential drug interactions or overdose.

In contrast, the patient's phone number is not a mandatory element on the prescription. While it may serve as a convenient method for follow-up communication, it is not a necessary detail to fulfill federal and state prescription regulations related to controlled substances.