Saavedra v. Eli Lilly & Co., 2013 U.S. Dist. LEXIS 173055 (C.D. Cal. Feb. 26, 2013):

The learned intermediary doctrine provides that a drug manufacturer has no duty to warn the ultimate consumer of potential side-effects of prescription medication, so long as adequate warnings are given to the prescribing physician. ***

In traditional tort cases (i.e. negligence or strict liability), the learned intermediary doctrine is determined either at summary judgment or at trial: upon proof that the drug manufacturer adequately warned prescribing physicians about potential side-effects, the manufacturer is immune from liability. Defendant urges this Court to take the learned intermediary doctrine a step further and find that it precludes Plaintiffs from stating a claim under the various consumer protection laws at issue in this case. The Court has not found, nor has Defendant identified, cases from the relevant jurisdictions addressing the question of whether  the learned intermediary doctrine prevents Plaintiffs from bringing their consumer protection claims altogether. When a case raises an issue of first impression, a court sitting in diversity "must use its best judgment to predict how the [relevant state] Supreme Court would decide the issue." Burlington Ins. Co. v. Oceanic Design & Const., Inc., 383 F.3d 940, 944 (9th Cir. 2004) (internal citations, quotation marks, and alterations omitted).   "In so doing, a federal court may be aided by looking to well-reasoned decisions from other jurisdictions." Id. (internal citations and quotation marks omitted).