Section 100.31 - Unfair discrimination in drug pricing(1) DEFINITIONS. In this section:(a) "Drug" means any substance subject to 21 USC 353(b) .(b) "Purchaser" means any person who engages primarily in selling drugs directly to consumers.(c) "Seller" means any person who trades in drugs for resale to purchasers in this state.(2) PRICE DISCRIMINATION PROHIBITED. Every seller shall offer drugs from the list of therapeutically equivalent drugs published by the federal food and drug administration to every purchaser in this state, with all rights and privileges offered or accorded by the seller to the most favored purchaser, including purchase prices for similar volume purchases, rebates, free merchandise, samples and similar trade concessions. Nothing in this subsection prohibits the giving of a discount for volume purchases.(3) TREBLE DAMAGES. Any purchaser damaged by violation of this section may bring an action against the seller to recover treble damages sustained by reason of such violation.(4) PENALTIES. For any violation of this section, the department or a district attorney may commence an action on behalf of the state to recover a forfeiture of not less than $100 nor more than $10,000 for each offense. Each delivery of a drug sold to a purchaser at a price in violation of this section and each separate day in violation of an injunction issued under this section is a separate offense.(5) SPECIAL REMEDIES. The department or a district attorney may bring an action to enjoin a violation of this section without being compelled to allege or prove that an adequate remedy at law does not exist. An action under this subsection may be commenced and prosecuted by the department or a district attorney, in the name of the state, in a circuit court in the county where the offense occurred or in Dane County, notwithstanding s. 801.50 .1975 c. 168, 421, 422; 1983 a. 188, 189; 1993 a. 352. "Most favored purchaser" under sub. (2) does not refer to purchasers outside Wisconsin. The constitutionality of this statute is upheld. K-S Pharmacies v. American Home Products, 962 F.2d 728 (1992).