Some insurance companies are restricting patients’ access to pain medicines with a lower risk of dependence or addiction, while making it easier to get generic opioid drugs, The New York Times reports.

Opioids drugs are generally less expensive than safer alternatives, the article notes. The New York Times and ProPublica analyzed Medicare prescription drug plans covering 35.7 million people. They found only one-third of people had access to Butrans, a painkilling skin patch containing buprenorphine, a less-risky opioid. Every drug plan that covered lidocaine patches, which are not addictive, but are more expensive than other generic pain drugs, required that patients get prior approval for the patches.

Almost all plans covered common opioids, and few plans required patients to obtain prior approval for them.