Rick, I've wondered that about ibuprufen with regard to another ailment that I can't think of now.

Similarly Zocor helps to prevent PD but Lipitor does not; both are statins. I think it's because Zocor gets in the brain easier.

Vioxx behaves very differently in the cardiovascular system than celebrex; both are cox-2 inhibitors. It's the law of unintended consequences. Some are good; others are not. Some Cox-2's are good at fighting cancer; others are not.

The makers of the drugs don't seem to spend much time worrying about unintended consequences. Only when they turn out to be good do they pay any attention, with research dollars. It's seems son, anyway.