Written by Samantha Farpour, L’26

Introduction

One-in-eight, or about 13%, of American adults have used a GLP-1 receptor agonist drug (GLP-1 RA), with higher percentages of younger adults using the drugs primarily for weight loss as compared to adults ages sixty-five years and older.^[1] The prevalence of GLP-1 RAs is such that Jan Hatzius, chief economist at Goldman Sachs, predicted a 1% boost  (amounting to several trillion dollars) in GDP if 60 million people take the medications by 2028.^[2] However, the widespread use of these “miracle” weight loss drugs may present serious health consequences. This blog post will predict key issues faced by plaintiffs pursuing claims in the ongoing multidistrict litigation against manufacturers of these drugs, and will argue that courts should recognize an exception to the learned intermediary doctrine for GLP-1 RA drugs.

Background on GLP-1 RAs

Ozempic, a brand name for an injectable form of the drug semaglutide, was manufactured by the multinational pharmaceutical company Novo Nordisk and initially designed to treat patients with type-2 diabetes.^[3] The drug skyrocketed in popularity after  a study published by the New England Journal of Medicine discovered its potential for weight loss.^[4] After only a few years on the market, thousands of Ozempic and Wegovy users reported experiencing gastrointestinal issues to the FDA. In August 2023, the first lawsuits were filed against Novo Nordisk, the manufacturer of Ozempic and Wegovy, as well as Eli Lilly, the manufacturer of similar GLP-1 agonist drugs.^[5] The lawsuits allege that Novo Nordisk and Eli Lilly failed to warn users that their products could cause gastroparesis and other gastrointestinal issues.^[6] In September 2023, the FDA updated the labeling for Ozempic to include a warning against ileus, or intestinal blockage, a condition characterized by an inability to move waste out of the body.^[7] In February 2024, these lawsuits were consolidated into multidistrict litigation (MDL) and centralized in the Eastern District of Pennsylvania. As of April 2025, there are 1,685 pending actions in the MDL with the U.S. District Judge Karen Marston as the presiding judge.^[8]

State Law Failure to Warn Claims

If the court rules that the failure to warn claims against Ozempic and Eli Lilly are not preempted by federal law, the plaintiffs may proceed on their state law failure to warn claims, which are premised upon the notion that pharmaceutical manufacturers have a duty to warn about the foreseeable risks associated with the drug. To succeed on a failure to warn claim, a plaintiff must prove that the pharmaceutical company failed to provide adequate warnings regarding the drug’s risks, that they suffered an injury, and that the failure to warn was the proximate cause of their injury.^[9] Proximate cause cannot be established if: “1) there is independent knowledge of the risk that the adequate warning would have addressed; or 2) the drug would have been prescribed by the patient’s physician or used by the patient even if an adequate warning were given.”^[10] If the failure to warn claims are not preempted by federal law, it is likely that Novo Nordisk and Eli Lilly will rely on the Learned Intermediary Doctrine in their defense. Rooted in common law, the Learned Intermediary Doctrine provides that a pharmaceutical company does not have a duty to warn the consumer directly and shifts the duty to warn onto the patient’s prescribing physician.^[11] Under the Learned Intermediary Doctrine, as long as the pharmaceutical company provides an adequate warning to the prescribing physician, the manufacturer of the drug is relieved of its duty to warn the actual consumer of the drug themselves.^[12] The majority of states follow the Learned Intermediary Doctrine in some form.

Learned Intermediary Doctrine and the Increase in Direct-To-Consumer Marketing of Pharmaceutical Products

The learned intermediary doctrine is premised upon the notion that physicians are in the best position to act as an “intermediary” between the prescription drug manufacturer and the patient, as they have the requisite training to provide individualized care to a patient based on direct contact and familiarity with the patient’s medical history and current status.^[13] The doctrine is rooted in several assumptions: (1) prescription pharmaceutical companies have less capacity to communicate efficiently with patients, (2) the average patient generally lacks the ability to understand the pharmaceutical company’s warnings and determine if the potential benefits of a particular drug outweigh the potential risks in the patient’s situation, and (3) physicians are in a better position to warn patients than pharmaceutical companies.^[14] Therefore, shifting the duty to warn onto the patient’s physician is consistent with the traditional physician-patient relationship.^[15] Prior to the inception of direct-to-consumer pharmaceutical advertising, drug manufacturers only gave information to doctors and pharmacists, and patients only received information about prescription drugs through their physician.^[16] Thus, a doctrine that shifted the duty to warn of a drug’s potential side effects from the manufacturer to a patient’s physician was reasonably prudent. However, the beginning of direct-to-consumer advertising and other modern technological advancements, the rising costs of delivering health care, and the reduced time doctors have to examine patients have altered the traditional dynamic of the doctor patient relationship, causing Americans to take a more active role in their health care decisions than in the past.^[17] It is important to note that the U.S. is one of only two countries in the world that allow direct-to-consumer advertising of prescription drugs.^[18] Due to the continually increasing interaction between pharmaceutical companies and consumers, critics of the doctrine and litigants who suffered injuries from prescription drugs have attacked it.^[19] They argue that the current era of excessive direct to consumer advertising means drug manufacturers should not be able to escape liability if they provided an adequate warning to physicians, but not to consumers.^[20]

Learned Intermediary Doctrine and Other Potential Challenges for Plaintiffs in the MDL

The learned intermediary doctrine, along with statutes of limitation, causation, and product identification, will likely be used in the early stages of the process to eliminate categories of claims.^[21] Many of the claims in the MDL allege symptoms of gastroparesis, a condition in which the stomach muscles cannot operate properly to digest food.^[22] Gastroparesis can result in a partially or completely paralyzed stomach and can cause nausea, vomiting, and stomach pain.^[23] The FDA-approved product labels for Ozempic, Wegovy, and Rybelsus do not warn of gastroparesis or gastrointestinal disease specifically.^[24] However, they do warn of gastrointestinal side effects, including “nausea, vomiting, diarrhea, abdominal pain, and constipation.”^[25] The warnings for drugs manufactured by Eli Lilly, namely, Trulicity and Mounjaro, warn of gastroparesis and other severe gastrointestinal reactions.^[26] One key issue may be whether these plaintiffs can establish a valid diagnosis of gastroparesis. Furthermore, the learned intermediary doctrine may complicate efforts of plaintiffs with these types of injuries to recover, because gastrointestinal issues are a well-known side effect of GLP-1 receptor agonists, making it more likely that a plaintiff’s prescribing physician had adequate warning of the risks.^[27]Even if a plaintiff can establish that the physician was not given an adequate warning of the risk, a plaintiff must still establish causation, which could also be complicated because gastrointestinal symptoms are exhibited frequently in people with type 2 diabetes, and people with type 2 diabetes are at an increased risk of developing gastroparesis.^[28] Some plaintiffs are alleging that the drug caused them to develop Ileus, which refers to a lack of movement in the intestine.^[29] If severe and untreated, an ileus can perforate the intestine, which can have deadly consequences.^[30] Unfortunately, persons with diabetes and persons with obesity are at a higher risk for Ileus, which may present issues regarding causation.^[31]

Exceptions to the Doctrine

Although the majority of states recognize the learned intermediary doctrine, some have recognized several exceptions, such as mass immunizations,  and oral contraceptives and devices, where patients play more active roles in choosing a product or they communicate less with their physician.^[32] Some courts have considered an exception where a pharmaceutical company has engaged in direct to consumer advertising, but the large majority of the jurisdictions have declined to recognize this exception, ultimately reasoning that public policy supports limiting the liability of drug manufacturers when they adequately warn prescribing physicians of the risks associated with drugs.^[33] Ultimately, arguments in favor of either abolishing the learned intermediary doctrine altogether or recognizing a blanket exception in cases where the pharmaceutical manufacturer has engaged in direct-to-consumer advertising are not sound as a matter of public policy.^[34] If tort liability were imposed on manufacturers for failing to warn consumers directly, manufacturers would have a strong incentive to over-warn, which could then encourage consumers to avoid taking medication altogether or could have the opposite effect of diluting more important risks, causing consumers to fail to appreciate their significance and potentially lead to inappropriate use. Thus, “[t]he continued value of the learned intermediary doctrine today is that it functions in tandem with FDA’s regulation of prescription drug labeling and advertising to help avert these undesirable outcomes.”^[35]

A New Level of Excessive Marketing: The Argument for an Exception in This Case

Although prescription drug advertising on social media and online platforms isn’t a new concept, the aggressive marketing employed by these major pharmaceutical companies to promote GLP-1 agonist drugs is arguably unprecedented.^[36] Since July 2018, Novo Nordisk has spent approximately $884 million to promote its pharmaceutical products on TV advertisements alone.^[37] The company also spent tens of millions of dollars by paying leading physicians to promote the drugs.^[38] In 2022 alone, the company paid $34 million to physicians for consulting, promotional speaking, and other non-research related work.^[39] However, the prolific advertising of the drugs on social media will likely be “front and center in the litigation,” given the increase in telehealth providers and the likelihood of patients using the drug without adequate warning of the risks.^[40] On popular social media platforms like YouTube and TikTok, paid online influencers infiltrated millions of user’s feeds with promotional content in the form of personal testimonials regarding the drug’s effectiveness for weight loss.^[41] These types of videos were often posted without clear disclaimers that the influencers were being compensated for their posts.^[42] The advertisements became so prevalent on TikTok that the popular social media platform had to update their guidelines on this type of promotional content, banning “before-and-after” photos, and filtering minors from viewing content that promotes “potentially harmful” weight-loss behaviors.^[43] The marketing tactics employed by Novo Nordisk are not only dangerous, but are arguably unethical.

Conclusion

The proliferation of misleading advertisements for GLP-1 RAs on social media, often from influencers & celebrities, warrants the recognition of an exception to the learned intermediary doctrine for GLP-1 RA drugs. First, physicians have indicated an increased pressure to prescribe and respond to demand from patients due to the surge in direct-to-consumer advertising of the drugs.^[44] Second, the increase in Telehealth and other digital avenues of obtaining the drugs indicates that physicians are less able to give personally-tailored warnings to patients.^[45] A 2025 analysis of the representation and characteristics of online listings of Ozempic found that “97.5% of programs were accessible remotely with no direct personal interaction with the company physician or supplier.”^[46] Lastly, the proliferation of misleading advertisements on social media illustrates that state law does not adequately regulate prescription drug advertising.^[47] The majority of advertising on social media was misleading because it focused more heavily on the benefits of the medication for weight loss rather than the risks.^[48] This situation differs from past pharmaceutical litigation because the drugs were marketed to a much larger class of people, including young teenagers, who are often more easily influenced.^[49] Ultimately, consumer use and sale of GLP-1 drugs indicates that consumers are often playing a very active role in choosing the drug, and are also communicating less with a physician, which are both reasons underlying why some states have recognized exceptions to the doctrine in other circumstances.^[50]  Given the pervasive use of these drugs, continually-evolving research raising other concerns about their risks, and likely challenges regarding causation for gastrointestinal injuries, it is imperative that the law protects consumers who have suffered injuries from the use of these medications.

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^[1] Shawn Radcliffe, How Common Are GLP-1 Drugs Like Ozempic? 13% of U.S. Adults Have Used Them, Healthline (May 13, 2024), https://www.healthline.com/health-news/how-common-are-glp-1-drugs-like-ozempic-13-of-u-s-adults-have-used-them.

^[2] Ariana Eunjung Cha, Weight-loss Drugs Aren’t Just Slimming Waists. They’re Shifting the Economy, Wash. Post (Feb. 23, 2025), https://www.washingtonpost.com/health/2025/02/23/ozempic-wegovy-change-life-spending/?utm_campaign=wp_news_alert_revere_trending_now&utm_medium=email&utm_source=alert&location=alert.

^[3] David Goguen, Are There Lawsuits Over Ozempic Side Effects?, Nolo, https://www.nolo.com/legal-encyclopedia/are-there-lawsuits-over-ozempic-side-effects.html (Aug. 26, 2024).

^[4] See John P. H. Wilding, et. al., Once-Weekly Semaglutide in Adults with Overweight or Obesity, 384 No. 11 New Eng. J. Med. (2021); see also Lewis Pennock, How Ozempic Took Over America: A $1BILLION Marketing Blitz and Millions Spent Lobbying Top Obesity Doctors Made Blockbuster Weight-Loss Drug A Cultural Phenomenon – That’s Even Joked About at the Oscars, Daily Mail, https://www.dailymail.co.uk/news/article-12970935/Ozempic-America-billion-marketing-obesity-Oscars.html (Jan. 24, 2024, 10:00 AM) (describing how Ozempic skyrocketed in popularity).

^[5] Jonathan D. Orent & Sarah O. Couch, Ozempic Lawsuit, Motley Rice, LLC, https://www.motleyrice.com/diabetes-lawsuits/ozempic (last visited Apr. 13, 2025).

^[6] MDL 3094 In Re: Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RAS) Products Liability Litigation,. E.D.. Pa, (last visited April 13, 2025), https://www.paed.uscourts.gov/mdl/mdl-3094-re-glucagon-peptide-1-receptor-agonists-glp-1-ras-products-liability-litigation.

^[7] Gigen Mammoser, Ozempic Label Updated to Include Blocked Intestines as Potential Side Effect, Healthline, https://www.healthline.com/health-news/fda-updates-ozempic-label-to-include-blocked-intestines-as-potential-side-effect (Oct. 2, 2023).

^[8] Orent & Couch, supra note 5.

^[9] See Bernard J. Garbutt III & Melinda E. Hofmann, Recent Developments in Pharmaceutical Products Liability Law: Failure to Warn, the Learned Intermediary Defense, and Other Issues in the New Millennium, 58 Food & Drug L. J. 269, 269-70 (2003).

^[10] Id. at 270.

^[11] Desiree A. Bsales, Learned Intermediary Doctrine in the Time of Direct-to-Consumer Drug Advertising, at iv (Apr. 2024) (MPH thesis, University of Pittsburgh).

^[12] Garbutt & Hoffmann, supra note 9 at 269.

^[13] See Id. at 272-73.

^[14] See Id.

^[15] Id. at 272-73.

^[16] Bsales, supra note 11 at 9.

^[17] See Id. at 25.

^[18] Glatter & Shah, Does Direct-to-Consumer Advertising Directly Harm Patients?, Time (Mar. 29, 2023, 7:00 AM), https://time.com/6266695/direct-to-consumer-advertising-harm-patients/.

^[19] See, e.g., Perez v. Wyeth Labs, Inc., 734 A.2d 1245, 1256 (N.J. 1999) (“Consumer-directed advertising of pharmaceuticals thus belies each of the premises on which the learned intermediary doctrine rests.”).

^[20] Robert B. Goetz & Karen R. Growdon, A Defense of the Learned Intermediary Doctrine, 63 Food & Drug L. J. 421, 428 (2008).

^[21] Robert King, Legal Analysis: Novo Nordisk and Eli Lilly Position Statement, King L., https://www.robertkinglawfirm.com/personal-injury/ozempic-lawsuit/court-filings/novo-nordisk-and-eli-lilly-position-statement/ (last visited Apr. 13, 2025).

^[22] Orent & Couch, supra note 5.

^[23] Gastroparesis, Mayo Clinic (Sept. 6, 2024), https://www.mayoclinic.org/diseases-conditions/gastroparesis/symptoms-causes/syc-20355787.

^[24] See King, supra note 20.

^[25] See Id.

^[26] See Id.

^[27] See Id.

^[28] Chinmay S. Marathe, et. al., Gastrointestinal Disorders in Diabetes, Nat. Libr. Med., https://www.ncbi.nlm.nih.gov/books/NBK553219/#:~:text=Gastrointestinal%20symptoms%20are%20exhibited%20frequently,and%20the%20patient%20populations%20studied (Feb. 22, 2024).

^[29] See King, supra note 20.

^[30] Rachel Nall, Ileus: Causes, Treatment, Symptoms, Diagnosis, and More, Healthline (Oct. 6, 2021), https://www.healthline.com/health/ileus.

^[31] Alyson Powell Key & Marijke Vroomen Durning, Ileus: What Is It?, Web MD (Dec. 4, 2023), https://www.webmd.com/digestive-disorders/what-is-ileus.

^[32] See, e.g., Reyes v. Wyeth Lab., Inc., 498 F.2d 1264, 1277 (5th Cir. 1974); Stephens v. G.D. Searle & Co., 602 F. Supp. 379, 380 (E.D. Mich. 1985).

^[33] See, e.g., Dearinger v. Eli Lilly & Co, 510 P.3d 326, 331 (Wash. 2022).

^[34] See Goetz & Growden, supra note 19, at 434-435.

^[35] Id. at 435.

^[36] See, e.g., Pennock, supra note 4.

^[37] See Id.

^[38] Id.

^[39] Id.

^[40] Social Media Ads Inject New Angle in Ozempic Cases: ‘It’s Going to Be a Huge Focus’, Law.com (Mar. 15, 2024), https://plus.lexis.com/document?pdmfid=1530671&pddocfullpath=%2Fshared%2Fdocument%2Flegalnews%2Furn%3AcontentItem%3A6BJV-2XN1-JBM3-R301-00000-00&pdcontentcomponentid=7599&ecomp=&earg=&prid=ae992851-80c5-490f-a0f9-4a5b6a660f12&crid=3bbf0ff1-c94c-481d-a0ba-dedb4dd9ca58&pdsdr=true#/document/b1b7881e-7758-4adb-8ac7-d22443819697.

^[41] Id.

^[42] Wilfred Chan, ‘I’m Not a Doctor Just FYI’: The Influencers Paid to Hawk Drugs on TikTok, The Guardian (Mar. 17, 2023), https://www.theguardian.com/us-news/2023/mar/17/patient-influencers-tiktok-instagram-medical-prescription-drug.

^[43] Ariel Zilber, TikTok Cracks Down on Social Media Influencers Pushing Ozempic, Wegovy, While Facing Potential U.S. Ban, MSN, https://www.msn.com/en-us/money/companies/tiktok-cracks-down-on-social-media-influencers-pushing-ozempic-wegovy-while-facing-potential-us-ban/ar-AA1nsTYx (last visited Apr. 13, 2025).

^[44] See Taylor Shaw, TikTok & Ozempic: CU Doctors Discuss Risks, Benefits of Advertising, Univ. of Colo. Dep’t. of Med. (June 3, 2024), https://news.cuanschutz.edu/department-of-medicine/research-impact-direct-consumer-advertising.

^[45] See Corey H. Basch et. al., Online Purchasing Options for GLP-1 Agonists: Accessibility, Marketing Practices, and Consumer Safety Concerns, J. of Med., Surgery, and Pub. Health Apr. 2025, at 2.

^[46] Id.

^[47] See Law.com, supra note 41.

^[48] Id.

^[49] Id.

^[50] See Reyes v. Wyeth Lab., Inc. & Stephens v. G.D. Searle & Co., supra note 33.