This commentary is by Diane Roston, who is on the clinical faculty at the Geisel School of Medicine at Dartmouth and is a physician at West Central Behavioral Health in Lebanon, New Hampshire. Imagine that when you go to pick up a refill, the pharmacist tells you that your insurance won’t cover it. “But I’ve been taking this medicine for years: two 10 mg tablets in the morning and one in the afternoon. It works well. And it’s generic,” you say, …