WASHINGTON — The Food and Drug Administration is requiring stronger warning labels on prescription painkillers like OxyContin, in the government’s latest attempt to reduce overdose deaths caused by the long-acting medications.

The changes announced Tuesday are designed to remind doctors and patients about the fatal risks of misusing and abusing long-acting opioid pain relievers, which include forms of oxycodone, morphine and other narcotic medications. The new label emphasizes that the drugs are only for patients with “around-the-clock” pain that cannot be treated with over-the-counter medications or immediate-release opioids.

“These labeling changes describe more clearly the risks and safety concerns associated with `extended release and long-acting’ opioids and will encourage better, more appropriate, prescribing, monitoring and patient counseling practices involving these drugs,” the FDA’s Dr. Douglas Throckmorton said in a statement.

The new label also includes a boxed warning about the risks of opioid withdrawal syndrome in infants who are exposed to the drugs during pregnancy, labor and nursing. Symptoms may include rapid breathing, trembling and poor feeding habits.

The FDA is also requiring manufacturers of the targeted products to conduct long-term studies tracking rates of misuses, abuse, addiction and death among patients.

Opioids are drugs that simulate the effects of natural narcotics, such as the opium poppy. They are typically prescribed for people already taking pain medications, including cancer patients, to treat severe pain flare-ups.

The FDA has issued a number of warnings about the dangers of prescription pain relievers in recent years, but with little effect. Inappropriate use of opioids caused more than 16,650 overdose deaths in 2010, up more than 12 percent from 2008, according to the Centers for Disease Control and Prevention.

Earlier this year the CDC reported that prescription painkiller overdose deaths among women increased about fivefold 1999 to 2010. Among men, such deaths rose about 3 1/2 times. The rise in both death rates is closely tied to a boom in the overall use of prescribed painkillers.

The most prescribed medication in the U.S. last year was the opioid combination pill Vicodin and its generic equivalents, according to IMS Health. U.S. pharmacies dispensed the medication, which combines hydrocodone and acetaminophen, over 135 million times in 2012. However, Tuesday’s announcement does not affect Vicodin because it uses an immediate release formulation.

The products targeted by the FDA feature extended-release formulations designed to give long-lasting effects. But that potency carries serious risks when doctors prescribe them inappropriately, and when patients abuse them as stimulants.

The FDA reports that many physicians prescribe the painkillers for unapproved uses, such as treating migraine headaches. Patients will also sometimes chew extended-release pills that are designed to be swallowed, causing an overdose.