Causation is a necessary element of a health care malpractice case. The plaintiff must show that the defendant’s error caused harm to the patient. The judge decides what testimony may be presented to the jury, and the jury makes the ultimate decision as to causation, based on testimony presented. However, on appeal, a judge’s decision about the admissibility of expert testimony is subject to challenge and reversal. A recent verdict against a hospital and pharmacy was reversed when the appellate court ruled that a pharmacologist should have been allowed to testify on behalf of the defense. An 82-year-old patient with a history of numerous cardiovascular disorders was admitted to the defendant hospital with a diagnosis of paroxysmal atrial fibrillation. His physician ordered oral amiodarone to be given as a loading dose in three separate administrations of 400 mg spread throughout the day. The patient was discharged with a prescription that directed: “1 tablet(s) oral (by mouth) as directed. 3 tablets a day for three days. 2 tablets a day for one week. 1 tablet daily thereafter.” The defendant pharmacy processed the prescription, placing on the medication vial a label that said: “Take 3 tablets by mouth for 3 days, 2 tablets once daily for 1 week, then 1 tablet once daily thereafter.” To avoid legal liability, whether due to a jury verdict or an out-of-court settlement, pharmacists need to ensure that patients understand the directions for using their medications. On the day of his discharge, the patient’s wife gave the patient three 400-mg tablets of amiodarone at 10:00 pm. The patient woke up at 2:00 am and slumped to the floor. He was again admitted to the hospital, and he suffered a stroke. He died just over a year later. The patient’s estate sued the hospital and the prescribing physician for “failing to specify that the amiodarone should have been taken in three separate doses throughout the day.” The estate sued the pharmacy and pharmacist for “negligently filling the prescription and indicating on the medication bottle that the amiodarone should be taken ‘once daily.’” A jury heard the evidence and submitted its verdict: “We, the jury, have concluded that the incorrect dose of amiodarone more likely than not did not cause [the patient’s] stroke; however, it more likely than not did cause harm.” The jury awarded just under $1 million in damages, assigning 75% fault to the hospital and physician and 25% fault to the pharmacy and pharmacist. The hospital appealed the verdict. The pharmacy settled out of court. The key issue on appeal was a ruling by the trial judge to exclude testimony of a pharmacologist who was offered as an expert by the defense. The judge concluded that the pharmacologist “did not demonstrate the requisite knowledge, experience, and training with the drug amiodarone.” The appellate court disagreed. The pharmacologist had a PhD in toxicology and pharmacology, had served as chair of the department of pharmacology and experimental therapeutics at a nearby medical school for more than a decade, and had published approximately 60 peer-reviewed journal articles. The court concluded that the trial court had “improperly conditioned [the pharmacologist’s] qualification upon specialization with the specific drug amiodarone.” As the pharmacologist was the only expert qualified to offer detailed testimony on the effects of amiodarone on the body, the exclusion of this relevant testimony from the jury’s consideration was prejudicial to the defense. The judgment of the jury was vacated, and the case was remanded to the lower court for a retrial. This case may ultimately be won by the defense. But the pharmacy has settled, and that will not be reversed. Lengthy and complicated directions are difficult to convey in a prescription label. To avoid legal liability, whether due to a jury verdict or an out-of-court settlement, pharmacists need to ensure that patients understand the directions for using their medications. A prescriber’s inclusion of the words “as directed” in a prescription provides no assurance that any directions have actually been given to the patient.