S.D. Codified Laws § 36-11-46.2
A practitioner may prohibit a pharmacist from selecting an equivalent drug product or interchangeable biological product by handwriting on the prescription drug order the words, brand necessary, or words of similar meaning. The prohibition may not be preprinted or stamped on the prescription drug order. This selection does not preclude a reminder of the procedure required for the practitioner to prohibit selection by a pharmacist from being preprinted on the prescription drug order. If an oral prescription is given to a pharmacist, the practitioner or practitioner's authorized agent shall instruct the pharmacist if selection of an equivalent drug product or interchangeable biological product is prohibited. The pharmacist shall note the instructions on the file copy of the prescription drug order.
SDCL 36-11-46.2