Also known as: manufacturer duty to warn · manufacturers' duty to warn · manufacturer's duty-to-warn · duty to warn · warning obligation
Written by attorneys · grounded in primary & secondary sources — see below
A products-liability obligation requiring a manufacturer to provide adequate warnings of known or knowable risks associated with its product when used in a reasonably foreseeable manner. In the context of prescription drugs and medical devices, the duty runs to the prescribing physician rather than the patient because the physician evaluates risks and benefits for the individual. Liability does not arise from a failure to warn the patient directly when the manufacturer supplies adequate information to the medical community.
Maxwell Manufacturing produced a prescription medication for hypertension. It supplied detailed risk information about potential liver damage to prescribing physicians but did not include patient-facing labels. Maya Malik later suffered liver failure after taking the drug as directed by her doctor. Her suit against Maxwell Manufacturing failed because the manufacturer had fulfilled its duty by warning the learned intermediary.
Mercury Industries manufactured an implantable cardiac device. It provided updated risk data on lead fracture to cardiologists but the warning omitted certain patient-specific factors. Mustafa Mahmoud received the device and later experienced a fracture that his physician testified would have prompted a different choice had the full warning been given. The court required Mustafa to prove that an adequate warning to the physician would have changed the prescribing decision.
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Morgan Financial developed an experimental cancer therapy with known but medically acceptable side effects. It furnished comprehensive data sheets to oncologists before any patient use. Marcus Mitchell received the therapy under his physician's care and later claimed inadequate warning. The manufacturer avoided liability because it had properly informed the learned intermediary about the recognized risks.
Midwest Airlines supplied maintenance equipment containing a latent defect to a tenant airline. It warned the airline's technical staff of the hazard but not individual mechanics. Miguel Mendoza, a mechanic, was injured when the equipment failed. The court applied the same principle that the duty runs to the intermediary with control over use decisions.
A cigarette manufacturer placed warnings on packages that complied with federal labeling statutes. Madison Meyers developed lung disease and argued the warnings were insufficient under state law. The manufacturer contended that federal requirements satisfied its duty to warn. The court examined whether the federal scheme displaced additional state tort obligations.
A manufacturer of insulation products containing asbestos continued distribution after internal tests revealed serious inhalation risks. Marco Marquez, a construction worker, developed asbestosis years later. The plaintiff argued the manufacturer should have warned users at the time of sale. The court considered whether the duty extended to risks discoverable only after initial marketing.
No. Under the learned intermediary doctrine, the duty runs to the prescribing physician, who evaluates risks and benefits for the individual patient. A manufacturer satisfies the duty by providing adequate warnings to the medical community.
The plaintiff must show that an inadequate warning to the physician would have altered the prescribing decision. Generalized evidence that the physician knew of some risks is insufficient to establish causation.
A manufacturer is not strictly liable for unfortunate consequences if the product is properly prepared, marketed, and accompanied by proper warning where the situation calls for it. The key is whether the warning to the learned intermediary was adequate given the known risks.
…of 1963. We shall conclude that plaintiffs' complaints state a cause of action against the psychotherapists for breach of the duty to warn Tatiana or her parents, but that they do not state a cause of action against the police for failure to warn or failure to confine. We further conclude that the police defendants are immune…