With that incidence, and the outcome of Donny Oregoni's case staring you in the face, if this question did not cause you to think about the significance of all those patients out there who may respond with elevated levels of drugs metabolized by CYP2D6, then apparently I did not succeed in making the point. By the way, another student suggested that this proved that both of Donny's parents were heterozygous for CYP2D6 mutation. There is another possibility. Remember, that CYP2D6 deficiency is not a disease. You can not tell these patients when they walk in the door.
Many people probably go through life never knowing that they are heterozygous - or homozygous.
Almost all of you who answered this question made the logical assumption that is correct in most cases. That is, unless otherwise mentioned, drugs are usually assumed to be given orally. However, some of you considered that the drug might be given IV and calculated it that way - that was OK as long as you noted that. I must apologize that I put a ringer into this question without meaning to. I did not mark off if you missed this subtle issue, but a few of you DID catch it, and it CAN be significant.