Be Careful What You Wish For: A Canadian Perspective on Direct-to-Consumer Advertising And The 'Learned Intermediary' Rule

By Barry Leon, Esq., and Cynthia Tape, Esq.*

Published in Andrews Litigation Reporter: Drug

Recall, June 2004.

"Our medical-legal jurisprudence is based on images of health care that no longer exist." So begins the judgment of the New Jersey Supreme Court in Perez v. Wyeth Laboratories Inc., the one court in the United States to hold that the manufacturer of a prescription drug may not rely on the "learned-intermediary" rule if it engages in direct-to-consumer advertising of that product.1

While no other U.S. court appears to have followed New Jersey's decision, significant changes in the marketing of prescription drugs and consumer participation in health care decision-making suggest that a re-evaluation of the learned-intermediary rule in Canada may lie ahead.

Rationale for the Learned-Intermediary Rule

Under Canadian law, the general rule is that the manufacturer of a product has a duty to warn the ultimate consumer of any material risks associated with the product's use. In the case of certain types of products, however, an exemption is granted where a "learned intermediary" inevitably intervenes between the manufacturer and the ultimate consumer. In that situation, "a manufacturer may satisfy its informational duty to the consumer by providing a warning to what the American courts have, in recent years, termed a 'learned intermediary.'"2

Thus, a prescription drug manufacturer can discharge its duty to warn by informing the prescribing physician (the classic learned intermediary) of the material risks. The rationale for the learned-intermediary rule was explained by the Court of Appeal for Ontario in Buchan v. Ortho Pharmaceutical (Canada) Ltd.:

[P]rescription drugs are more likely to be complex medicines, esoteric in formula and varied in effect and, by definition, are available only by prescription. The prescribing physician is in a position to take into account the propensities of the drug and susceptibilities of his patient. He has a duty of informing himself of the benefits and potential dangers of any medications he prescribes, and of exercising his independent judgment as a medical expert based on his knowledge of the patient and the product. In taking the drug, the patient is expected to, and it can be presumed does, place primary reliance on his doctor's judgment.3

Exception for Certain Types of Drugs

In keeping with this rationale, the learned-intermediary rule has been applied in the context of prescription drugs and medical devices but not to intermediaries in other contexts.4 The defense may not, however, apply to all prescription drug products.

Buchan involved the adequacy of the warnings given by Ortho Pharmaceutical to consumers and physicians about certain risks associated with an oral contraceptive product. In considering the learned-intermediary rule, the Court of Appeal noted that most jurisdictions in the United States recognized the rule without exception. However, a number of state courts had established an exception in the case of oral contraceptives because those courts...