Another question that was raised at grand rounds was why the FDA approved the 150 mg dose but not the 110 mg dose.
Representatives of the FDA addressed that very question in a NEJM article last year. They noted that the consequences of ischemic stroke are more devastating than non-fatal hemorrhage. They then considered 3 sub-populations in whom the lower dose (which was “non-inferior” to warfarin in preventing strokes with a lower bleeding risk) might be preferred: Elderly patients, those with impaired renal function, and those with a prior hemorrhage history. In each case, they found the higher dose to have the superior risk/benefit profile. They conclude:
Ultimately, the FDA’s decision to approve only the 150-mg strength was based on our inability to identify any subgroup in which use of the lower dose would not represent a substantial disadvantage.