The learned intermediary doctrine has been adopted in some form by courts in all fifty states. It provides an exception to the traditional rule in products liability law that manufacturers have a duty to warn the ultimate consumer, and it precludes manufacturer liability for failure to warn the consumer when an adequate warning has been given to a “learned intermediary.” This places the physician directly in the crosshairs of liability.
The Learned Intermediary doctrine paints an idyllic picture of patients’ total reliance on their physicians to choose drugs and of physicians choosing drugs that best promote patient welfare. These images, however, are increasingly out of sync with the present-day healthcare system. For instance, managed care and other cost control measures employed by insurance companies have altered the doctor-patient relationship. Often times, the insurance companies provide a formulary which limits the drugs that a physician can prescribe.
Traditionally, the protection that the doctrine affords has been based on the premise that prescribing physicians act as learned intermediaries between manufacturers and consumers. Therefore, physicians stand in the best position to evaluate patients’ needs, and assess risks and benefits of particular courses of treatment. And if the product is properly labeled with the appropriate warnings and instructions to fully inform the physician of the risks involved and the procedures for use, the manufacturer may reasonably assume that the physician will exercise his/her informed judgment in the patient’s best interests.
All Drugs Do Harm
The bottom line is that the physician is legally accountable for all drugs that he prescribes, including injuries that arise out of a failure to warn. This is a standard that is impossible to meet. To illustrate this enormous hole in our healthcare system, I’ll use as an example, the most benign drug that I can think of – aspirin. Aspirin has been around since the 1890’s. It’s use is ubiquitous – it is present in the medicine cabinets of most households. More recently, aspirin has been found to be the only drug (out of hundreds of heart medications) that actually increases the life expectancy of cardiac patients. A daily aspirin is also a proven prophyaxis against colon cancer. Other effects include: pain relieving, anti-inflammatory, anti-platelet, anti-stroke, ad infinitum. The list is impressive and it’s safety has withstood the test of time.
However, consider the potential side effect profile of aspirin (taken from Lexicomp drug formulary – not an exhaustive list):
Bleeding: bleeding is associated with aspirin, namely upper and lower GI bleeds.
Cardiovascular: Cardiac arrhythmia, edema, hypotension, tachycardia
Central nervous system: Agitation, cerebral edema, coma, confusion, dizziness, fatigue, headache, hyperthermia, insomnia, lethargy, nervousness, Reye’s syndrome
Dermatologic: Skin rash, urticaria
Endocrine & metabolic: Acidosis, dehydration, hyperglycemia, hyperkalemia, hypernatremia (buffered forms), hypoglycemia (children)
Gastrointestinal: Gastrointestinal ulcer (6% to 31%), duodenal ulcer, dyspepsia, epigastric distress, gastritis, gastrointestinal erosion, heartburn, nausea, stomach pain, vomiting
Genitourinary: Postpartum hemorrhage, prolonged gestation, prolonged labor, proteinuria, stillborn infant
Hematologic & oncologic: Anemia, blood coagulation disorder, disseminated intravascular coagulation, hemolytic anemia, hemorrhage, iron deficiency anemia, prolonged prothrombin time, thrombocytopenia
Hepatic: Hepatitis (reversible), hepatotoxicity, increased serum transaminases
Hypersensitivity: Anaphylaxis, angioedema
Neuromuscular & skeletal: Acetabular bone destruction, rhabdomyolysis, weakness
Otic: Hearing loss, tinnitus
Renal: Increased blood urea nitrogen, increased serum creatinine, interstitial nephritis, renal failure (including cases caused by rhabdomyolysis), renal insufficiency, renal papillary necrosis
Respiratory: Asthma, bronchospasm, dyspnea, hyperventilation, laryngeal edema, noncardiogenic pulmonary edema, respiratory alkalosis, tachypnea
Miscellaneous: Low birth weight
Post-marketing and/or case reports: Anorectal stenosis (suppository), atrial fibrillation (toxicity), cardiac conduction disturbance (toxicity), cerebral infarction (ischemic), cholestatic jaundice, colitis, colonic ulceration, coronary artery vasospasm, delirium, esophageal obstruction, esophagitis (with esophageal ulcer), hematoma (esophageal), macular degeneration (age-related), periorbital edema, rhinosinusitis
Hypersensitivity to NSAIDs; patients with asthma, rhinitis, and nasal polyps; use in children or teenagers for viral infections, with or without fever.
Documentation of allergenic cross-reactivity for salicylates is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.
- Bleeding disorders: Use with caution in patients with platelet and bleeding disorders.
- Dehydration: Use with caution in patients with dehydration.
- Ethanol use: Heavy ethanol use (>3 drinks/day) can increase bleeding risks and may enhance gastric mucosal damage.
- Gastrointestinal disease: Use with caution in patients with erosive gastritis. Avoid use in patients with active peptic ulcer disease.
- Hepatic impairment: Avoid use in severe hepatic failure.
- Renal impairment: When using high dosages (eg, analgesic or anti-inflammatory uses), use with caution and monitor renal function or consider the use of an alternative analgesic/anti-inflammatory agent (NKF [Henrich 1996]; Whelton 2000).
Concurrent drug therapy issues:
- Alteplase: In the treatment of acute ischemic stroke, avoid aspirin for 24 hours following administration of alteplase; administration within 24 hours increases the risk of hemorrhagic transformation (Jauch 2013).
- COX-2 inhibitors/NSAIDs: When used concomitantly with ≤325 mg of aspirin, NSAIDs (including selective COX-2 inhibitors) substantially increase the risk of gastrointestinal complications (eg, ulcer); concomitant gastroprotective therapy (eg, proton pump inhibitors) is recommended (Bhatt 2008).
- Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
This is a partial list of side effects of a “benign or safe” drug. The point that I am making is that every drug ever discovered has a laundry list of potential side effects. In general, while it’s always best to avoid prescribing a drug when possible, this is not a practical. After all, for an internist such as myself, this is our primary offensive weapon. Patients are dissatisfied if they leave the office without a prescription.
It is not feasible to inform on every drug that is prescribed. The average medical practice would come to a stand-still. On the other side, side effects are a potential reality. They can happen. You just never know when they will.
If a physician were to attempt to go through the list of side effects, the patient would almost certainly be frightened off, her ailment might be left untreated, and she would likely never return. She would be denied essential therapies for real diseases. If I were to inform a patient with pneumonia that the drug of choice, Levofloxacin, can cause prolonged Q-T interval, cardiac arrhythmia and death; and she refuses treatment; she stands the real chance of dying from pneumonia (which accounts for over 20,000 deaths in the US annually).
An informed consent “gap” exists between theory and practice — physicians do not and cannot adequately inform most patients about a prescription drug.
The learned intermediary rule is undoubtedly the most significant attribute that distinguishes product liability litigation involving prescription medical products from other product liability litigation. The rule dates from the middle of the Twentieth Century and is “based on the principle that prescribing physicians act as ‘learned intermediaries’ between a manufacturer and consumer and, therefore, stand in the best position to evaluate a patient’s needs and assess the risks and benefits of a particular course of treatment. Manufacturers are relieved of their duty to ensure that the adequate warning reaches the patients to whom the physician prescribes the drug. A manufacturer’s duty to warn is generally satisfied when the manufacturer warns the physician.
While learned intermediary doctrine looks good on paper, it is practically implausible. Courts should eliminate the increasingly anachronistic Learned Intermediary doctrine. Instead, the responsibility should be shared between pharmaceutical manufacturer, the physician, pharmacist and patient.