Senator Says F.D.A. Asked Canada Not to Suspend Drug

Sen Charles Grassley says FDA officials asked Canadian regulators not to pull hyperactivity drug Adderall XR from market because agency could not handle another 'drug safety crisis'; bases contention on reports from whistle-blowers within FDA; Dr Robert Peterson, Health Canada official, disputes statement and FDA declines to respond directly; FDA is allowing drug to continue to be sold in US, and says there is little evidence that it caused 20 deaths that precipitated Canada's recall; Grassley demands that FDA answer questions about discussions officials may have had with Canadians about drug; Shire Pharmaceuticals maintains drug is safe and effective; photo (M)
http://query.nytimes.com/gst/abstract.html?res=F00F12F93C5E0C728DDDAB0894DD404482