Drugmaker Eli Lilly is significantly lowering the prices of the two lowest doses of its blockbuster weight loss drug Zepbound, it said Tuesday, in a move to expand access and ease supply constraints. Two key changes to how people get and use the cheaper medicine, however, might not be appealing to some patients.

Under the new pricing plan, a month’s supply of the lowest dose, 2.5 milligrams, will cost $399, while a month’s supply of the 5 mg dose will cost $549. That’s down from a…