The learned intermediary rule has long served as an effective antidote to lawsuits based on a pharmaceutical manufacturer's liability for a claimed failure to warn. The doctrine, which provides that a manufacturer discharges its duty to warn a patient of potential adverse reactions by warning the patient's physician, is accepted in most American jurisdictions.¹ Thus, a manufacturer of medicines or devices is not liable for claims based on a failure to warn if the prescribing physician is adequately warned about the adverse reaction claimed in a lawsuit.

However, despite its firm roots in American jurisprudence, new challenges to the learned intermediary rule can be expected due to an evolving health care delivery system, a complex and constantly changing statutory and regulatory scheme, and widespread patient access to information via the Internet. Each of these factors has promoted patient awareness and facilitated an increased role for the patient in making decisions about his or her own health care.

II.The Learned Intermediary-An Overview

A physician's decision of whether to prescribe a medicine or medical device is a highly personal one, dependent on an often unique set of facts, including the patient's condition; how efficacious the proposed treatment is; what the odds are of an adverse reaction; and how much, if anything, a patient should be told about potential adverse reactions. In analyzing these questions, a physician will recognize that one of the few absolutes in science is that "a medicine safe for all is effective for none."² In light of these realities, the courts acknowledge that a manufacturer of a medicine or medical device has two obligations: to make a medicine or device that is not impure or defective, and to warn about all known or scientifically knowable risks involved in the use of the medicine or device. The law of the learned intermediary recognizes the variables inherent in prescribing medications and acknowledges that if a physician is warned about an adverse reaction, the manufacturer of the medicine or device is not liable to the patient if the patient experiences this reaction.

The rationale underlying the learned intermediary rule is that only physicians and other health care professionals can assess the specific risks and benefits of a prescription medication for each patient. In Carmichael v. Reitz, a historic California case, the court of appeals reiterated the multitude of rationales for the learned intermediary rule:

(1) The doctor is intended to be an intervening party in the full sense of the word. Medical ethics as well as medical practice dictate independent judgment, unaffected by the manufacturer's control, on the part of the doctor. (2) Were the patient to be given the complete and highly technical information on the adverse possibility associated with the use of the drug, he would have no way to evaluate it, and in his limited understanding he might actually object to the use of the drug, thereby jeopardizing his life. (3) It would be virtually impossible for a manufacturer to comply with the duty of direct warning, as there is no sure way to reach the patient.³

The learned intermediary rule was first articulated a half century ago in the New York case of Marcus v. Specific Pharmaceuticals, Inc.,⁴ and the phrase "learned intermediary" was introduced in Sterling Drug, Inc. v. Cornish.⁵ The Proposed Final Draft of the American Law Institute's Restatement (Third) of Torts: Products Liability has recently ratified the learned intermediary rule and its rationales, further entrenching the rule into American jurisprudence.

III. Ratification by the Restatement

The overall health of the learned intermediary doctrine is reflected in the draft of the Restatement (Third) of Torts: Products Liability, approved by the American Law Institute in May 1997.⁶ While not binding law in any jurisdiction, the Restatement is persuasive authority and carries immense credibility in advancing policy arguments in product liability cases. Section 6 of the Restatement addresses the unique liability of a manufacturer of a medicine or a medical device. Quite simply, such a manufacturer is liable for an injury caused by a defect.⁷ The definition of a defect explicitly includes inadequate instructions or warnings.⁸ The Restatement also recognizes the role of the learned intermediary in dispensing such warnings, thereby relieving the manufacturer of the duty to warn the patient directly.⁹

The evolution of the Restatement (Third) clarifies several aspects of the learned intermediary doctrine as it was ultimately approved. An early draft suggested that the learned intermediary rule should not apply when Food and Drug Administration ("FDA") regulations required the manufacturer to provide the patient with direct warnings, or where the manufacturer had engaged in direct-to-consumer advertising or promotion of the drug or device.¹⁰ However, the final draft eliminated these suggested exceptions. The comments indicate that "developing case law" should determine the applicability of the learned intermediary rule in these situations.¹¹ Recent case law appears to be split on the issue of the applicability of the learned intermediary rule where the FDA has mandated that certain warnings be given. For instance, in Edwards v. Basel Pharmaceuticals,¹² a case involving a Habitrol nicotine patch, the Oklahoma Supreme Court noted that jurisdictions were split on this issue, but ultimately held that the learned intermediary rule does not apply when the FDA has mandated specific warnings.¹³

As Edwards demonstrates, any exception for FDA-mandated warnings and direct-to-consumer advertising could effectively swallow the learned intermediary rule. This becomes an even greater threat as the FDA plays an increased role in regulating direct-to-consumer advertising, as well as the content of pharmaceutical and device information on the Internet. Thus, the conscious choice of the drafters not to recommend exceptions in these instances may prove to be very important in defending the applicability of the rule.

Another noteworthy development in the Restatement is the expansion of the medical personnel to whom warnings must be given to satisfy the manufacturer's duty. Section 6 makes it clear that the manufacturer must warn not only the prescribing physician but also "other health care providers who are in a position to reduce the risks of harm in accordance with the instructions or warnings."¹⁴ This mandate extends the duty to warn to all health care providers who could potentially advise the patient about the ill effects of a medicine. These new intermediaries would include such health care professionals as nurse-practitioners and medical staff in other environments (such as birth control clinics) in which the physician is not the only health care provider to advise patients about the risks and benefits of specific prescriptions.

However, the overall effect of the Restatement favors prescription drug and medical device manufacturers by reaffirming the learned intermediary rule, and explicitly refraining from recommending new exceptions which could limit or eviscerate the rule.

IV. Exceptions to the Rule

Although the ratification of the learned intermediary rule in the Restatement is clearly favorable, this does not mean that assaults on the rule have ceased or that nicks in the defense do not exist. Over the years, courts have carve out narrow exceptions to the rule that are recognized by the Restatement. A guiding principle in assessing these exceptions is that the less physician involvement in providing a medicine, the greater the corresponding responsibility for the manufacturer to provide a warning directly to the patient. Cases which espouse this tenet are premised on the theory that if no medical personnel are available to provide independent and individual medical judgment to a patient, the manufacturer has a duty to warn the patient directly of the medicine's risks.

A. Mass Immunization

The classic setting for this exception is the mass immunization clinic, where no individual patient assessment by a physician is conducted, and all comers are given the vaccine. Here, courts have held that the manufacturer of the vaccine must provide a warning directly to all patients, and cannot rely on the learned intermediary rule to escape liability for an adverse reaction. In such a setting, no intermediary is involved in the prescribing decision.¹⁵ However, at least one jurisdiction has held that the learned intermediary rule applies when a vaccine was given as p art of a local immunization program. Specifically, in Walter v. Merck & Co., Inc.,¹⁶ the district court held that the learned intermediary rule applied to the polio vaccine in a case which involved a local immunization program, and not a "massive, nationwide program" typical of other polio vaccine cases. It stated that:

Because the [vaccine] program was aimed at select students in Bibb County only, it would be highly impracticable, if not impossible, for Merck to determine which students would need to receive the vaccine, and then to warn each recipient individually. Although the court realizes that Merck conceivably could have taken other measures to warn high school students in Bibb County about the risks inherent in [the polio vaccine], such measures would be extreme and would place an undue hardship on manufacturers of inherently dangerous drugs. This case clearly falls within the ambit of the learned intermediary rule.¹⁷

The National Childhood Vaccine Injury Act of 1986 has further narrowed the exception by eliminating the requirement of direct warnings for seven compulsory childhood vaccines, effectively codifying the learned intermediary rule into law.¹⁸

B. Birth Control

Another exception to the learned intermediary rule has been contemplated by several jurisdictions for oral contraceptives, but has been recognized in only one jurisdiction. In creating this exception, the Massachusetts Supreme Court in MacDonald v. Ortho Pharmaceutical Corp.¹⁹ discussed three "peculiar characteristics" that distinguish oral contraceptives from other prescription medicines to which the learned intermediary doctrine undoubtedly applies. Those characteristics include the active role a patient plays in requesting birth control measures, as opposed to the relatively passive role of a physician prescribing it; the length of time oral contraceptives may be used with minimal physician monitoring; and the FDA requirement that manufacturers of contraceptives ensure that users are provided enough information to make an informed choice based on a clear knowledge of the medicine's potential side effects.²⁰

Later cases in other jurisdictions have refused, however, to adopt the oral contraceptive exception. Moreover, in the recent case of Gurski v. Wyeth-Ayerst Division of American home Products,21 a trial court in Massachusetts appeared to be close to reconsidering the learned intermediary exception for oral contraceptives when the medicine was initially prescribed for therapeutic purposes, not birth control. In Gurski, the plaintiff first took Ovcon-35, an oral contraceptive, to control menstrual discomfort. When she later became sexually active, she used the prescription for birth control. She later switched to Triphasil²¹, another oral contraceptive. The patient eventually developed a liver tumor and sued the manufacturer of the medicine even though the product literature for both contraceptives contained warnings about this risk. The defendant moved for summary judgment because the oral contraceptive exception to the learned intermediary rule articulated in MacDonald did not apply when the contraceptive was prescribed for therapeutic purposes. Although the court said that, at "first blush," the factors that led to the exception might not apply in such a case, it refused to grant summary judgment, stating that "there may be a duality to the use, as here, which might blur any legal distinction."²² While the court declined to narrow the oral contraceptive exception in this case, it appears open to the possibility of doing so upon a clearer factual showing of therapeutic use.²³

The possible reconsideration of the oral contraceptive exception by the Massachusetts courts is consistent with a judicial hesitancy to restrict the application of the learned intermediary rule in cases involving other types of birth control products.²⁴ This hesitancy is further evidenced by the recent ruling in the first Norplant cases, in which the multidistrict litigation ("MDL") court upheld the applicability of the learned intermediary rule for this device.

The case also provides a rationale for the application of the rule in cases involving direct-to-consumer advertising and promotion of a medicine or medical device on the Internet. Norplant is a medical device consisting of six matchstick sized capsules implanted under the skin of a woman's arm, which secret levonoro-gestrel into the body for birth control purposes.²⁵ The Norplant litigation is based on allegations that the device caused side effects ranging from headaches to strokes. The plaintiffs pled a variety of claims that include theories of strict product liability, negligence, breach of warranty, fraud, misrepresentation, and violation of deceptive trade practices acts.²⁶ In the first set of summary judgment motions on failure to warn claims, the Norplant MDL court ruled that the learned intermediary rule applied as a matter of law and refused to fashion an exception based on the argument that an aggressive direct-to-consumer marketing scheme displaced the role of the physician as intermediary.²⁷

In rejecting this argument, the court held that although Norplant was marketed through extensive direct-to-consumer advertising, the defendant's conduct did not displace the role of the physician in prescribing and implanting Norplant, and in discussing side effects with patients. Specifically, the court reasoned that "prescribing physicians have a duty to discuss the risks and benefits of Norplant with each patient. Clearly, Norplant is administered in the context of a physician-patient relationship . . . Moreover, if any physician allowed himself to become a mere conduit for Wyeth's materials, then it is the physician who is responsible."²⁸ Once again, the common denominator for the application of the defense is that the rule will apply if a health care provider is involved in the therapy decision.

Other recent case law has also extended the learned intermediary doctrine or clarified its breadth. The 1994 California case of Ramirez v. Plough, Inc.²⁹ establishes that the failure to provide a warning in a language other than English is not actionable. A Fourth Circuit³⁰ case holds that if a clear instruction for the use of a device is given to a learned intermediary who is himself the user of the medical device, a warning about a product's misuse need not be issued. A Pennsylvania court has ruled that a manufacturer's duty to warn does not create a duty to recommend an antidote if a patient experiences an adverse effect about which the manufacturer warned.³¹ Finally, a Georgia court held in Presto v. Sandoz Pharmaceuticals that a manufacturer has no duty to directly warn patients of the dangers of a discontinued drug.³³

V. Component Part Manufacturers

Further demonstrating the universal acceptance of the learned intermediary rule, the applicability of the rule has been broadened to address the issue of whether a manufacturer of a component of a device must warn about the risks of the component.³³ Generally, these cases have recognized that a manufacturer of a component discharges its duty to warn the end user by warning an appropriate intermediary. In such cases, the intermediary is in a far better position to warn the end user of a product's risks than is the manufacturer of the component. Accordingly, the raw material supplier defense provides that the supplier of a raw material used as a component in a finished product, such as Teflon in temporomandibular joint ("TMJ") implants or silicone in breast implants, is not required to warn the patient about the finished product's risks.

Courts have articulated several policy reasons for this expansion. First, the imposition of liability on a component part manufacturer, based on the knowledge of the final product's design, would force it to either remain ignorant of the final product's design, or to become an expert about the final product's design. These alternatives would either discourage a component manufacturer from becoming aware of safety issues that might present themselves in the end product, or would impose an unreasonable burden on the component manufacturer to educate itself about every potential use of end products. The second rationale is that a component part often has many industrial uses, only a small percentage of which might be dangerous. The third and final rationale is that the end product manufacturer is often in a far superior position to properly warn users of hazards associated with the product designed for use by the consumer.

The 104th Congress attempted to enact the raw material supplier defense into the Product Liability Reform Act of 1997, which would have applied to manufacturers of biomaterials suppliers whose products are used to make medical implants. Suppliers of such materials would have been immune from product liability lawsuits except where the supplier was itself the manufacturer or seller of the final product, or where the supplier furnished raw materials which failed to meet applicable contractual requirements or specifications.³⁴ However, the Act as a whole failed when the Congress adjourned at the end of the legislative year.³⁵

VI. Potential Exceptions on the Horizon

Overall, the learned intermediary doctrine remains robust and firmly established despite the creative attempts of plaintiffs' attorneys to chisel away at the rule by arguing for new exceptions or limitations. Such exceptions await in issues surrounding the changes in providing health care, in FDA regulation of direct-to-consumer advertising, and in cyberspace.

The past decade has seen a multitude of changes that have affected the traditional physician-patient relationship and the process by which medicines and devices are selected and prescribed. A recent New York Times headline epitomizes the change: "New Prescribing Just What the Patient Ordered. Telling the self-educated patient, 'Watch two ads and call me in the morning.'"³⁶ Consumers and patients today reject the idea that "the doctor knows best." They want to be involved in the treatment decision, and often times their zeal has resulted in the patient knowing more about a therapy than a physician. This appetite for participation has been fed by demands of consumer groups for information and by the adoption of statutes requiring full treatment disclosure, as well as the opening of the airwaves, the print media, and the Internet. Each of these may have an effect on the continued vitality of the learned intermediary rule unless practitioners and the courts remind themselves of the vitality of the rule's rationale.

A. Changing Health Care Delivery Systems

Just as an exception to the learned intermediary rule was developed in mass vaccination clinics due to the diminished role of the physician, larger changes in the health care delivery system present analogous situations in which the role of the physician can be said to be nonexistent. Such clinical settings pose a potential threat to the learned intermediary rule.

Several commentators have proposed that the learned intermediary rule should be abolished, pointing to the previous trend of exceptions for vaccines and oral contraceptives. In a consumer-oriented nation, they advocate that the patient should be the final decisionmaker about risks and benefits of medication.³⁷ One writer suggests that principles of informed consent³⁸ are more appropriate than the learned intermediary rule because the assumptions on which the rule are premised do not apply to modern health care delivery systems. Specific health care delivery issues that may fuel these attacks and render the learned intermediary rule inapplicable include the role of managed care in creating incentives for physicians to treat with less expensive medications, rather than what a physician might prefer to prescribe.³⁹ The decreasing likelihood of establishing a long-term relationship with a particular physician, because a patient's choice of physician is sometimes constrained by insurance companies,⁴⁰ is also relevant.

Other commentators point out that even before managed care, doctors simply did not have the time to be fully informed about all side effects of medications, and did not adequately take time to fulfill their duties of informed consent.⁴¹ In the era of managed care, these proponents argue that a patient is well-advised to learn as much as possible about a medicine and make as many informed decisions as possible about the care he or she is to receive. A corollary to such consumerism is that the learned intermediary rule is an anachronism because patients need as much information as possible to make an informed choice. Thus, the manufacturer should be accountable directly to the patient and should provide the patient with as many opportunities as possible to obtain necessary information.⁴² The Restatement, however, implicitly negates these postulates and, while expanding the scope of who an intermediary is, refuses to require full disclosure to the patient.

B. FDA Regulation

FDA regulation of pharmaceutical and medical device manufacturers will continue to influence the scope of the learned intermediary doctrine, and play an immense role in the future vitality of the defense.⁴³ FDA regulations requiring specific warnings on certain products, such as oral contraceptives, have already been found to abrogate the learned intermediary rule in some jurisdictions. However, the FDA's regulation of direct-to-consumer advertising may create a policy argument in favor of strengthening the learned intermediary doctrine to counter a dilution of the defense proposed by plaintiffs. One of the stated rationales for these regulations is that they ensure that the physician-patient relationship is not undermined by pharmaceutical advertising. Further, the potential for FDA regulation of the Internet content of manufacturers' pages will likely enhance the applicability of the learned intermediary doctrine, as patients increasingly use the Internet to obtain information about pharmaceutical products.⁴⁴

Some courts have unrealistically held that FDA regulations requiring manufacturers to provide specific information to users effectively abrogate the learned intermediary rule.⁴⁵ For example, the 1997 case of Edwards v. Basel Pharmaceuticals⁴⁶ discusses the FDA-mandate exception, stating that:

We hold that when the FDA requires warnings be given directly to the patient with a prescribed drug, an exception to the "learned intermediary doctrine" has occurred, and the manufacturer is not automatically shielded from liability by properly warning the prescribing physician. When this happens the manufacturer's duty to warn the consumer is not necessarily satisfied by compliance with FDA minimum warning requirements.⁴⁷

Edwards also notes several cases from other jurisdictions, some of which recognize an FDA mandate exception to the learned intermediary rule, and others that refused to adopt this exception.⁴⁸

The 1996 California Supreme Court case of Carlin v. The Upjohn Company⁴⁹ also addressed the impact of FDA-mandated warnings. The court held that a strict liability standard exists for failure to warn about known or reasonably knowable risks, and that FDA regulations do not expressly preempt common law tort remedies for failure to warn. It did acknowledge that a manufacturer may not be held liable for a failure to give a warning if it has been expressly precluded by the FDA. The implications of Carlin for manufacturers of prescription products are problematic, since plaintiffs may rely on either FDA regulations or common law tort remedies to attempt to establish liability.

The Carlin endorsement of strict liability for failure to warn about known or reasonably knowable risks is a minority position.⁵⁰ The majority view, as affirmed in the Washington case of Young v. Key Pharmaceuticals, Inc.,⁵¹ holds that negligence principles apply and that the jury should consider the reasonableness of the manufacturer's conduct because "comment k imposes liability only for negligence, not strict liability."⁵² The Restatement (Third) is aligned with the majority approach, and one commentator correctly refers to the majority rationale as a "more enlightened approach."⁵³

C.Direct-to-Consumer Advertising

The relatively recent phenomenon of direct-to-consumer advertising raises similar questions about the applicability of the learned intermediary rule. Over the last decade, pharmaceutical manufacturers have increased direct advertising to the public.⁵⁴ In 1996, pharmaceutical companies in the United States spent $595 million on direct-to-consumer advertising, a significant increase over the $11.9 million spent on such advertising just seven years earlier.⁵⁵ Plaintiffs' attorneys may attempt to argue that where direct-to-consumer advertising has occurred, an exception to the learned intermediary rule should be created.⁵⁶ Although relatively little case law addresses this subject, a few courts have considered the effects of marketing and have found that, in some contexts, it can serve as a basis for liability.⁵⁷

Defenders of pharmaceutical companies can assert many strong policy arguments against an exception to the learned intermediary rule for direct-to-consumer advertising, as demonstrated by the recent Norplant cases granting summary judgment based on the applicability of the learned intermediary rule.⁵⁸ Direct-to-consumer advertising does not displace the physician; patients may become aware of new prescription medications, but they must still see a doctor in order to obtain a prescription. The FDA has also regulated direct-to-consumer advertising, creating a voluntary preclearance program for print advertisements⁵⁹ and issuing broadcast guidelines, with a recently published draft guidance entitled Consumer-Directed Broadcast Advertisements.⁶⁰ Further, direct-to-consumer advertising is economically feasible for only a small percentage of prescription products, and these products do not play a particularly significant role in the product liability landscape.⁶¹ Finally, the Restatement does not endorse such an exception, but rather leaves the issue to be determined by developing case law.⁶² The underlying argument which can always be made in defending the learned intermediary rule's applicability is that direct-to-consumer advertising (or whatever the proposed exception might be) does not significantly alter the physician-patient relationship.⁶³

D. The Learned Intermediary and the Internet

The increased presence of pharmaceutical manufacturers on the Internet, and the movement toward regulation of pharmaceutical manufacturers' web sites, will likely affect the future of the learned intermediary defense. The Internet has become a vital means to obtain up-to-date information quickly. Moreover, nearly 25 percent of all Internet traffic is health related.⁶⁴ Pharmaceutical companies use the Internet as a means of disseminating information and news about various topi