Greg Presto's mental illness was being treated with Clozaril, an antipsychotic medication manufactured by Sandoz Pharmaceuticals Corp. Because Clozaril can damage a patient's immune system, pharmacists and nurses at Caremark, Inc., a distributor of the drug, dispensed the medicine, drew Greg's blood each week, monitored the results of those tests, and provided the results to Dr. Warren, the prescribing physician. The Clozaril helped Greg's condition, but it had undesirable side effects. Greg and his mother requested that Greg be taken off the medication, and Dr. Warren allegedly agreed. In August, 1991, Greg stopped taking the medication, but he failed to heed the warning included in the drug's packaging to gradually reduce the dosage over a one- or two-week period lest the patient's psychotic symptoms recur. Greg committed suicide. The Prestos sued Sandoz, alleging that the manufacturer failed to warn Greg of the dangers he faced if he discontinued use of the drug suddenly. What defense might Sandoz raise? How should the court rule on this claim?