Which of the following is NOT required by law to be on a prescription?

The patient's phone number is not a requirement specified by law to be included on a prescription. While having the patient's contact information can be helpful for the pharmacy to verify details or if they need to reach out for any inquiries, it is not mandated by regulatory standards.

On the other hand, the date of issue is a critical element because it establishes the timeline for the prescription's validity and is essential for determining the appropriate refill intervals and expiration. The name and strength of the drug are also crucial components, as they provide specific information necessary for the dispensing of the medication intended for the patient. Finally, a signature from the prescriber is required for written prescriptions to confirm authenticity and authority for the medication prescribed, ensuring that the pharmacy is fulfilling a legitimate and legal order.