Final answer:
A pharmacist must adhere to patient privacy laws, such as HIPAA, when considering disclosing information about a patient's substance abuse treatment to a physician, only sharing when legally permitted or required.
Step-by-step explanation:
A pharmacist's ability to disclose information to a treating physician about a patient receiving a prescription drug for substance abuse treatment involves considerations of patient privacy laws and professional ethical standards. In the United States, this situation is generally guided by the Health Insurance Portability and Accountability Act (HIPAA) which protects certain health information.
Unless the patient has provided consent or as per state laws and regulations which include specific exemptions, disclosing this type of sensitive information may be restricted. Pharmacists are required to adhere to these regulations and should ensure that any disclosure of patient information is compliant with the law and done in the patient's best interest.