To establish the defendant’s wrongful act was the but-for cause of the plaintiff’s injury, but not the proximate cause, the defendant has would need to prove that the physicians who prescribed Neurontin for off-label purpose used their own judgement to prescribed Neurontin to patients instead of other drugs in the market. In addition, if Pfizer had not directly targeted physicians to promote off-label use, the causation of Kaiser’s injury may still have occurred but it would not have been the proximate cause of the injury since physicians would have been the prescribing authority to decide what should be prescribe.
