Onlooker Asked: What happened to excedrin extra strength?

I take extra strength Excedrin caplets for bad headaches, and am about to run out, but now it appears that no one is selling them–at least not Drugstore.com, Amazon.com, and Walmart.com was selling them as clearance items, but is out of stock. Despite their expense, I always found them the best aspirin for a headache, better than Excedrin migraine. What happened to Excedrin extra strength? Any ideas?