What must be written on a prescription for generic substitution to be overridden for Medicare and Medicaid patients?

For generic substitution to be overridden for Medicare and Medicaid patients, it is essential for the prescription to include the notation that indicates brand medication is medically necessary. This ensures that the pharmacist is aware that the patient cannot receive a generic alternative due to specific medical reasons, which could include considerations of efficacy, tolerability, or potential drug interactions.

When the prescriber indicates "Brand medically necessary," it legally protects the prescriber’s directive to dispense the brand-name drug rather than allowing a generic substitute. This is especially relevant in programs like Medicare and Medicaid, where regulations around medication dispensing are stringent, and the patient's health outcomes must be prioritized.

The other options do not carry the authoritative weight needed to override the usual preference for generic medications. Phrases like "Substitution allowed," "Generic necessary," and "Patient preference" do not communicate a medical necessity that would justify the additional cost and potential insurance complication for the patient when a generic alternative may be available. Hence, the correct phrasing to ensure adherence to the medical need is the one that specifies the necessity of the brand-name medication.