Nevada courts have long applied the learned intermediary rule to pharmacists filling prescriptions, and now another federal district court has ruled that the doctrine applies to drug manufacturers, too.  This is not surprising, since other federal judges have similarly predicted that Nevada’s Supreme Court would apply the learned intermediary rule to drug and medical device manufacturers.  But as we have said in our learned intermediary state survey, Nevada’s a little strange.  It is helpful to have one more.

The case is Stephens v. Zoetis, Inc., No. 2:25-cv-00989, 2026 WL 837353 (D. Nev. Mar. 25, 2026), where a federal judge in Nevada dismissed an economic loss class action brought by a dog owner against the manufacturer of a veterinary medicine after her pet experienced harmful side effects.  She claimed that the manufacturer failed to warn of either those side effects or “hundreds of additional incidents,” and she sought to recover economic losses on the theory that neither she nor the putative class of dog owners would have purchased the medicine if the manufacturer had adequately warned.  She likewise alleged that no reasonable, properly warned veterinarian would have prescribed the medicine, either. 

The district judge first ruled that the learned intermediary doctrine applies to drug manufacturers, following others in the district.  Although the court mistakenly called the doctrine an “affirmative defense,” it accurately described the rule, which “defines the scope of a manufacturer’s duty to warn in the context of prescription drugs or medical devices . . . by providing that the manufacturer’s duty to warn runs to the physician, not to the patient.”  Id. at *2 (emphasis in original, citations omitted). 

The Nevada Supreme Court applied the learned intermediary rule to pharmacists in 2011, in a case called Klasch v. Walgreen Co., on the well-established reasoning that the doctrine prevents drug dispensers from “constantly second-guessing a prescribing doctor’s judgment simply in order to avoid his or her own liability to the customer.”  Id.  The same rationale applies to drug manufacturers:  “A drug manufacturer, like the pharmacist, is not in the best position to weigh the risks and benefits of a drug in a particular patient, while a learned intermediary like a doctor or veterinarian has the benefit of knowing the patient’s specific situation.”  Id. (citations omitted). 

The learned intermediary doctrine therefore applied, and it barred the plaintiff’s claims.  To start, the product’s labeling listed every side effect and symptom alleged in the complaint.  In fact, the plaintiff did not identify any specific risk or symptom that was not included. 

Moreover, a stronger or different warning would not have altered the veterinarian’s decision to prescribe the drug.  The plaintiff alleged that the labeling did not adequately convey the severity of the risk, citing “hundreds” of adverse event reports.  But veterinarians have prescribed tens of millions of doses of this particular product, so warning of “hundreds” of additional events would raise the potential risk by something like a thousandth of a percent.  As the court concluded, “It is simply not plausible that such an imperceptible increase in risk would be relevant information to a prescribing physician or that this missing information would’ve altered the veterinarian’s decision.”  Id. at *3. 

This is a classic application of the learned intermediary rule and a dead-on example of warnings causation:  A stronger warning would not have made a difference, so any alleged inadequacy in the warnings could not have caused any harm.  As the court put it, this plaintiff could not tie the alleged inadequacy in the warning to her theory of recovery.  And, in Nevada (and elsewhere), the plaintiff in a product liability failure-to-warn case “carries the burden of proving, in part, that the inadequate warning caused [her] injuries.”  Id. (citation omitted).  This is the correct allocation of the burden—i.e., despite the court’s loose language, the learned intermediary rule is not a defense.  The cherry on top is that the court denied leave to amend.  The plaintiff did not explain how any amendment could fix her “learned-intermediary-doctrine or causation issues.”  And more specific allegations could not show how a veterinarian’s knowledge of a “near-imperceptible increase in risk” would have altered prescribing decisions.  Id. at *4.  We award Stephens v. Zoetis a blue ribbon.