Vt. Stat. tit. 18 § 4606
If the prescriber has determined that the generic equivalent of a drug or the interchangeable biological product for the biological product being prescribed has not been effective or with reasonable certainty is not expected to be effective in treating the patient's medical condition or causes or is reasonably expected to cause adverse or harmful reactions in the patient, the prescriber shall indicate "brand necessary," "no substitution," "dispense as written," or "DAW" in the prescriber's own handwriting on the prescription blank or shall indicate the same using electronic prescribing technology and the pharmacist shall not substitute the generic equivalent or interchangeable biological product. If a prescription is unwritten and the prescriber has determined that the generic equivalent of the drug or the interchangeable biological product for the biological product being prescribed has not been effective or with reasonable certainty is not expected to be effective in treating the patient's medical condition or causes or is reasonably expected to cause adverse or harmful reactions in the patient, the prescriber shall expressly indicate to the pharmacist that the brand-name drug or biological product is necessary and substitution is not allowed and the pharmacist shall not substitute the generic equivalent drug or interchangeable biological product.
18 V.S.A. § 4606