Therapeutic substitution and the hospital formulary system.

Physicians consent and statutory regulations relating to therapeutic substitution are discussed. Some hospitals have adopted policies allowing the interchange of a chemically inequivalent product deemed therapeutically identical by the P & T committee. In the absence of statutory regulation, hospital pharmacists usually refer to (1) the physician's agreement to abide by hospital bylaws (including the formulary system) when joining the hospital staff, or (2) prescription blanks and order sheets preprinted with the statement "substitution permitted unless otherwise indicated" as the legal authority for therapeutic substitution. Only two states have addressed the legality of therapeutic substitution. An opinion of the Oregon Attorney General and a Washington state statute both authorize therapeutic substitution under certain circumstances if the prescriber has given prior consent. Neither of the states specifies, however, whether the agreement of prescribers to abide by hospital bylaws constitutes authorization of therapeutic substitution. It is proposed that state boards of pharmacy and state legislatures draft laws that address therapeutic substitution and specify acceptable methods of consent.