How demanding is the causation standard in a California failure to warn claim when a learned intermediary testifies that he would have read and incorporated more stringent warnings if they had been available? Is the plaintiff required to show that the stronger warning would have altered the physician’s decision to prescribe the product? Or may the plaintiff establish causation by showing that the physician would have communicated the stronger warnings to the patient and that a prudent person in the patient’s position would have declined the treatment as a result?
The Ninth Circuit isolated this undefined causation standard in Himes v. Somatics, LLC, and certified the question to the California Supreme Court. After confirming that the learned intermediary doctrine is alive and well in California and that a failure to warn claim cannot survive when the learned intermediary does not read the warnings at all, the Ninth Circuit stopped short of defining the causation standard that applies when a learned intermediary does read the warnings.