Generic Prescribing, Generic Substitution, and Therapeutic Substitution

Abstract

Pressures generated by a constellation of professional consumer, legislative, and health care provider vider groups in this era of increasing health care costs have led to enactment of generic substitution laws in 50 states. The general acceptance of this concept, despite conflicting evidence that it has reduced the cost of prescription items to the consumer, has led to the concept of therapeutic substitution. Considerable confusion exists among health care professionals regarding the precise meaning of these concepts. Generic prescribing is the prescribing of a drug by a physician using the generic name. This leaves the choice of brand to the dispensing pharmacist. Generic substitution is a pharmacist-initiated act by which a different brand or an unbranded drug product is dispensed instead of a drug brand that was prescribed by the physician. This means substituting the same chemical entity in the same dosage form for one marketed by a different company. Therapeutic substitution is a pharmacist-initiated act by which a pharmaceutical or therapeutic alternate for the physician-prescribed drug is dispensed without consulting the physician. This denotes replacement of the prescribed drug with a chemically different drug within the same therapeutic category, eg, hydrochlorothiazide for furosemide; ranitidine for cimetidine; chloramphenicol for erythromycin. In 1976, the AAP Committee on Drugs published a commentary in Pediatrics (1976;57:275-277) on generic prescribing and concluded that "the lack of data on bioavailability and bioequivalence in children precludes blanket support of generic prescribing for infants and children." The Committee recently reviewed this issue and concluded that the situation has changed little during the past decade.