FEW BLESSINGS of modern science are entirely unmixed, and so it is with the development of powerful synthetic or semi-synthetic opioid analgesics — painkillers such as fentanyl and hydrocodone. Prescribed by the tens of millions in recent years for their power to relieve otherwise crippling pain in the victims of disease and injury, these pills have turned into a $7.3 billion-per-year business. Yet they also pose a major public health risk because of their ready availability and addictiveness to many patients.

In fact, abuse of prescription medications is overtaking that of “street drugs” such as heroin and cocaine. The Centers for Disease Control and Prevention (CDC) spoke of a pain-pill overdose “epidemic” that cost 15,000 lives in the United States in 2008, up from 4,000 in 1999. Nearly half a million emergency-department visits in 2009 were because of people misusing or abusing prescription painkillers, according to the CDC, while nonmedical use of prescription painkillers costs health insurers up to $72.5 billion annually.

On Thursday, the Food and Drug Administration (FDA) announced an important action aimed at reversing this dangerous trend. The FDA recommended that the federal government add so-called hydrocodone combination products to the list of Schedule II drugs, which would make it significantly more difficult for people to obtain more than a 90-day supply without visiting a doctor for a new prescription; no phone or fax prescriptions would be allowed. Under current rules, it is possible to get six months’ worth of pills on a single, refillable prescription.

Unlike pure hydrocodone, which was already on Schedule II because of its high potential for abuse, the combination products, with trade names such as Vicodin or Lortab, include an opioid and a non-narcotic such as acetaminophen. In 2011, they were the most frequently prescribed medications in the United States, according to the Drug Enforcement Administration (DEA). But an FDA advisory panel found that the combination products are more habit-forming and susceptible to wider abuse than previously thought. The FDA recommendation is not the government’s final word on the subject, but the DEA and Department of Health and Human Services are likely to ratify it.

The only bad news is that it took so long for the federal bureaucracy to reach this sound conclusion. The DEA asked the FDA to reevaluate the scheduling of hydrocodone combination products four years ago, when the prescription-drug epidemic was well underway. Congress also weighed in, in the form of proposed legislation by then-Rep. (now Sen.) Edward J. Markey (D-Mass.) and Rep. Vern Buchanan (R-Fla.). But opponents ranging from pharmaceutical companies to the American Cancer Society objected that tighter controls would unduly inconvenience patients. Actually, the FDA’s decision represents a modest step toward controlling the black market. It won’t stop “doctor shopping” by drug-seeking patients; probably nothing could.

The FDA has struck the right balance, based on its correct assessment that the public interest lies not in more use of pain medicines but in the proper use of them.