Consumers and policymakers both recognize that careful balancing will be necessary to “bend the curve” on health-care costs without harming patient care. How careful? For a good illustration, consider the buzz saw the Centers for Medicare and Medicaid Services, CMS, has run into with a proposal to save money by changing the requirements for Medicare coverage of certain drugs.

Currently, Medicare requires that insurers offering drug plans under Medicare Part D cover virtually all prescription drugs used to treat six categories of diseases, among them schizophrenia and other mental illnesses, cancer, transplant rejection and seizures. In January, CMS proposed a rule change that would remove the coverage requirement for three of the drug categories, including anti-psychotic drugs.

The federal agency argues that the coverage requirement was a temporary measure in 2006 to aid implementation of the new drug program. The officials contend the covered drugs may represent as much as one-third of Part D outpatient spending, at a cost 10 percent higher on average than it would be without the requirement.

Relevant also is a well-recognized dynamic in driving up costs: Drug companies, knowing nearly all the drugs in the categories are covered, are less inclined to negotiate significantly lower prices with insurers.

These are not an unreasonable basis for a policy review, to be sure. That said, with the proposal to scrap required coverage for anti-psychotic and other drugs, the federal agency risks being penny wise and pound foolish at the expense of highly vulnerable patients. Opponents of the policy change point out correctly that treating mental illness, in particular, is a highly individualized process, which often involves trying out different medications to find an effective combination. Limiting access to the full range of available drugs thus could throw treatment into a tailspin.

The effort to contain costs is, perhaps, the most challenging aspect of health reform. The Affordable Care Act rightly casts a wide net in seeking cost savings in the federal health programs. Still, the quest for savings does not diminish the responsibility to avoid doing harm.