Product Liability Suits Involving Drug or Device Manufacturers and Physicians: The Learned Intermediary Doctrine and the Physician’s Duty to Warn

Introduction

Robert Larkin became paraplegic after a 1964 car accident.¹ Due to his paraplegia, Larkin suffered significant musculoskeletal pain. Larkin was treated by the same internist beginning in 1988. Over the years, the physician prescribed a variety of nonsteriodal antiinflammatory drugs to treat Larkin’s pain.

In July 1998, Larkin visited his physician, complaining of a head cold and exhibiting symptoms of blisters in his mouth and on his arms and legs. The physician prescribed separate medications to treat Larkin’s apparent sinus infection and his blistering.

Larkin’s condition did not improve. In late August 1998, Larkin again visited his physician. He complained of sinusitis and shoulder pain. For the sinusitis, Larkin’s physician gave him a six-pill sample of Zithromax, an antibiotic manufactured by Pfizer, Inc. For the shoulder pain, Larkin’s physician changed his anti-inflammatory medication to Daypro, a drug manufactured by G.D. Searle & Co.

Over the next few months, Larkin began to develop fluid-filled blisters over a large portion of his body. When the blisters drained, Larkin’s skin sloughed off. Larkin’s physician diagnosed him with toxic epidermal necrolysis (“TEN”), and its milder form known as Stevens-Johnson syndrome. TEN is a severe and sometimes life-threatening condition, which is often drug-induced. More than 100 drugs - including Zithromax and Daypro - have been implicated in TEN cases.

Prior to his TEN diagnosis, Larkin had been able to move about with crutches. After his TEN diagnosis, and several weeks in a hospital burn unit to treat and eventually reduce his direct TEN symptoms, Larkin exhibited substantially decreased stamina and became wheelchair-bound.

In late 1999, Larkin sued Pfizer and Searle for his injuries, alleging that Zithromax and Daypro were defective and unreasonably dangerous products, thereby causing his injuries. Pfizer and Searle successfully insulated themselves from liability, however. The manufacturers argued that Larkin’s doctor knew that TEN was a risk associated with both Zithromax and Daypro, and that he failed to warn Larkin of this risk because he believed that the risk was insignificant. After years of litigation, Larkin was unable to recover damages from the manufacturers. Multiple courts sided with the manufacturers’ argument, concluding that the buck stopped with the physician.²

The Role of the Learned Intermediary Doctrine in Drug or Device Product Liability Suits

The argument made by Pfizer and Searle in the Larkin case - known as the “learned intermediary” doctrine - is very common in cases involving injuries allegedly caused by a prescription drug or medical device. In a typical case, an injured patient files suit against all parties in the “chain of distribution” of the drug or device, from the manufacturer down to the physician. But, because the ultimate treatment decision is made by the physician in the course of the doctor-patient relationship, the manufacturer of a drug or device is routinely able to avoid liability by “blaming the physician.”

In this regard, a manufacturer generally contends that, so long as the manufacturer transferred the drug or device to the treating physician with adequate accompanying information (including warnings about any risks), subsequent treatment decisions made by the physician break the line of causation between the manufacturer and the patient. An injured patient, unable to demonstrate causation, is then unlikely to prevail on a claim that his injuries resulted from the manufacturer’s conduct. An injured patient’s claim against his physician arising from the same injury, however, often survives. This places great pressure on physicians to reach settlements with patients in such suits.³

The learned intermediary doctrine is settled law in an overwhelming majority of states, including Missouri.⁴ It limits a drug or device manufacturer’s duty to warn of its product’s risks to treating physicians, who then serve as “learned intermediaries,” assuming the duty to pass those warnings on to patients.

Three basic and related rationales have, historically, supported the learned intermediary rule. First, the treating physician is in a superior position to impart warnings to patients, and to exercise her independent medical discretion in determining whether a treatment is appropriate for a particular patient.⁵ Second, manufacturers lack effective means to communicate directly with each patient.⁶ Thirdly, imposing a duty to warn on the manufacturer would unduly interfere with the doctor-patient relationship.⁷ Further, as a corollary, some courts have expressed concern that, since the typical manufacturer’s warning may list scores of potential side effects regardless their probability, lay consumers might overreact to a manufacturer’s warning and forego critical treatment.⁸

In short, with few exceptions, a manufacturer relieves its duty to warn patients by providing adequate warnings to treating physicians, whether or not those physicians adhere to the warnings and communicate them to their patients.

The Learned Intermediary Doctrine and the Pressures and Consequences of Physician Settlements in Product Liability Suits

Because the physician is often the last defendant standing in drug or device “chain of distribution” suits, the eventual pressure on a physician to settle with an injured plaintiff is, again, strong. And a separate rule, known as the “settlor-barred” doctrine, commonly prevents a physician from, later, seeking contribution from the manufacturer to offset her losses.⁹

A Missouri “chain of distribution” suit illustrates this rule well.¹⁰ In 1978, a physician at Cardinal Glennon Hospital in St. Louis administered Orimune, an oral polio vaccine, to three-month old Danny Callahan. Callahan appeared to be in good health following the vaccination, until approximately one month later, when he was diagnosed with an unrelated perirectal abscess. Following protracted treatment of the abscess, Callahan contracted polio, which permanently paralyzed his legs and left arm. A jury concluded that the hospital had been negligent in treating Callahan’s abscess, and that this negligence suppressed Callahan’s immune system, rendering him susceptible to the live polio virus in the vaccine.

The doctor settled with Callahan prior to trial for $290,000. The doctor then sued the manufacturer and distributor of Orimune - American Cyanamid Company and Hesselberg Drug Company, respectively - seeking contribution from them to offset his $290,000 settlement. The Missouri Supreme Court concluded that the “settlor-barred” doctrine, which prevents a settling defendant from recovering from a third party unless he has relieved the third party of liability to an injured plaintiff, prohibited the doctor’s contribution claims against American Cyanamid and Hesselberg. The court explained that, by settling with Callahan, the doctor “discharged only his liability … and protected himself from contribution claims of other defendants.” But, equally, settling with Callahan barred the doctor “from seeking contribution from American Cyanamid or Hesselber.”¹¹

A clear consequence of this settlement bar is that the pressure on physicians to settle in drug or device suits is paired with an element of finality. Settlement will almost always prevent a physician from, subsequently, seeking contribution from a drug or device manufacturer. This is true regardless the merits of a physician’s claim, because the physician speaks only for her own conduct, not a manufacturer’s.

How Physicians Can Better Protect Themselves From Liability in Drug or Device Product Liability Suits: Satisfying the Duty to Warn

In light of the shifting of accountability from manufacturers to physicians in drug or device product liability suits, as well as the resulting pressure on physicians to settle and the finality of settlement, it is critical for physicians to safeguard themselves by meeting their duty to warn patients of the risks and side effects associated with a prescription drug or medical device.

Although no legal outcome is certain, there are sensible steps that physicians should take in an effort to satisfy their duty to warn patients:

• Stay informed of FDA drug and device recalls and FDA-approved drug and device labeling requirements.

• Keep abreast of drug and devices manufacturers’ product disclosures and warnings. Also, date and archive manufacturers’ disclosures and warnings for recordkeeping purposes.

• Determine if additional information regarding a drug or device is available, including studies suggesting risks or dangers that the FDA has yet to act on.

• Require patients to provide a list of all prescription and over-the-counter drugs being taken. Relatedly, inform patients of potential drug-food and drug-drug interactions.

• Advise patients of other treatment options available and the medical rationale for the one being used.

• Document all disclosures and warnings made to patients.

• Instruct patients to read drug labels.

• Provide patients with simplified drug or device instructions (e.g., dosing instructions) in writing.

• Obtain written informed consent from patients when prescribing a drug or using a medical device for an off-label purpose.

• Seek legal or risk management guidance when uncertainties arise.

The law is well settled that physicians have a primary duty to warn patients about the risks and complications associated with prescription drugs and medical devices. While legal arguments have been made -by both injured patients and physicians themselves -that manufacturers should be responsible for this duty to warn, courts continue to hold physicians accountable. Common-sense measures, like those set forth above, are essential for physicians to meet their legal duty to patients when patient treatment involves prescription drugs or medical devices.

Biography

Jason Husgen, JD, is an Associate and member of the Healthcare, Life Sciences & Pharmaceuticals industry team at Husch Blackwell LLP in St. Louis. The Firm acts as outside general counsel to the Missouri State Medical Association.

Contact: jason.husgen@huschblackwell.com

The information contained in this article should not be construed as legal advice or legal opinion on any specific facts or circumstances. The contents are intended for general informational purposes only, and readers are encouraged to consult their own attorney regarding specific legal questions.