A long-awaited study has found that two of the main medications for treating opioid addiction are similarly effective. The study, funded by the federal government, compared Vivitrol, which comes in a monthly shot and blocks the effects of opioids, and Suboxone, which is taken daily in strips that dissolve on the tongue and contains a relatively mild opioid that helps minimize withdrawal symptoms and cravings.

Researchers found that 52 percent of those who started on Vivitrol relapsed during the 24-week study, compared with 56 percent of those who started on Suboxone.

But the study, according to a report yesterday in The New York Times conducted with 570 adults addicted mostly to heroin, also found a substantial hurdle for Vivitrol. Because the medication can be started only after a person is completely detoxed from opioids — a process that can take over a week — more than a quarter of the study participants assigned to Vivitrol dropped out before being able to take their first dose. Suboxone can be started shortly after withdrawal symptoms begin, and only six percent of those assigned to take that drug dropped out before taking an initial dose.

Drug manufacturers have been competing fiercely to develop and market medications to treat opioid addictions, which have propelled a steep increase in the number of drug deaths in the United States. Last year, 64,000 Americans died from drug overdoses, up 22 percent from the previous year.

There is significant money at stake, according to the Times story. Under a law passed by Congress in 2016, the Trump administration is sending $1 billion to states to deal with the epidemic over the next two years, with directions to prioritize so-called medication assisted treatment. Mr. Trump’s opioid commission recentlyimplored Congress to swiftly appropriate more money.

Suboxone, made by Indivior, is the older, cheaper, and much more widely studied and used of the two medications. The manufacturer of Vivitrol, Alkermes, has tried to catch up by marketing its drug as a cleaner alternative, emphasizing that Vivitrol is the only federally approved addiction medication that does not contain an opioid.

Vivitrol is also the most expensive addiction medication, with Medicaid paying about $500 per shot, according to Alkermes, and private insurers paying $1,000. Suboxone tends to cost a third to half as much. Another addiction medication approved by the Food and Drug Administration, methadone, is much cheaper, but people who take it have to go to specially licensed clinics for their daily dose. The study focused on Vivitrol and Suboxone because both can be prescribed by primary care doctors, although a federal waiver is needed to prescribe Suboxone.

Photo, courtesey Brian Snyder/Reuters.