Learned Intermediary
Another facet of misuse is the expected expertise of the user. Historically, pharmaceutical manufacturers were allowed to assume that their drugs would be prescribed by physicians who were trained in pharmacology. This allowed the drug manufacturers to assume that warnings and other information would be read by an expert who could understand medical terminology and who would independently determine the suitability of the drug for the individual patient. This is called the “learned intermediary doctrine,” and it insulates drug manufacturers from liability for physicians who incorrectly prescribe drugs, as long as the physician was provided the necessary information to prescribe the drug properly. In contrast, when drugs are sold over the counter (i.e., without a prescription), they must be labeled so that any consumer can use them safely. As drug manufacturers increase their direct marketing of prescription drugs to consumers, the courts are limiting
their ability to claim the learned-intermediary defense. In a recent case, a state court found that the manufacturer of Norplant, a subcutaneous, long-term contraceptive, would be limited in the way it used the learned-intermediary defense because it advertised the product directly to consumers. The court allowed the patients to argue that the manufacturer
should have provided safety information directly to the patients, rather than only to the physicians prescribing Norplant.
The courts have never clearly adopted the learned intermediary defense for medical devices. This is partially because, unlike pharmacology, physicians do not receive any training in clinical engineering. It also is due to the broader user base for medical devices. Unlike prescription drugs, which until recently were only prescribed by physicians, medical devices were frequently used by nurses and technicians who came from various backgrounds. Without a learned intermediary defense, medical device manufacturers must design and label devices so that they can be safely used by nonphysicians. This has become a particular problem as medical devices are routinely used in home health care, often without a medically trained user. Such uses demand well-designed training materials, device manuals, and labels on the device for safe use. The courts consider these explanatory materials as part of the device itself. If they are inadequate or do not provide appropriate information for the actual users of the device, they will be considered defective. Many medical device claims are based on defective labeling, rather than defects in the physical device itself.