Drug Scheduling Decisions Must Follow the Science

Earlier this month, the R Street Institute urged lawmakers to follow the science when it comes to drug scheduling rather than rushing ahead with decisions that could inadvertently make our communities and loved ones less, not more, safe. We submitted a congressional letter to Senate leadership asking them to respect the intent of our standard drug scheduling process—which explicitly includes an eight-factor evaluation by the Department of Health and Human Services (HHS). The HHS analysis considers drugs’ pharmacological characteristics, effects on humans, and subsequent risk for misuse and harm and is used as the basis for the agency’s scheduling recommendations. In addition, in an effort to improve transparency around the matter, we filed a Freedom of Information Act request to the HHS, calling on them to provide the status, results, and recommendations related to any scientific and medical analysis they have already completed for xylazine, as well as any relevant dates.

Why Does This Matter?

Congress is considering placing the veterinary sedative colloquially known as “tranq” on the Controlled Substances Act (CSA) alongside Schedule III drugs. While lawmakers’ concerns are understandable—almost 110,000 people in the United States died of a drug overdose in 2023, and xylazine has become an increasingly common and complicating adulterant—such action would not reduce overdose risk or the presence of illicit drugs in our communities. Furthermore, by deprioritizing scientific evaluation just when we need it most, these actions would potentially create long-term harms.  

Available research indicates that xylazine is not a likely candidate for misuse on its own. Xylazine is almost always mixed with other criminalized substances, especially fentanyl, and the vast majority of people who use drugs do not seek it or necessarily know it is in their supply. In fact, many actively try to avoid it due to concerns about excessive sedation and soft tissue injury. It is reasonable to assume that, based on these criteria, the HHS would not consider xylazine to be a drug with comparable potential for misuse as, say, ketamine (another Schedule III drug).

But there is another reason Congress should wait for scientific assessment before placing xylazine on the CSA: Scheduling itself does not reduce harm and, in some cases, can put our loved ones and communities at increased risk.

One quick look at recent U.S. drug policy will reveal that increased criminalization is not an effective way to stem the rise of the potent synthetic substances that dominate our illicit drug market. Federal efforts to place all fentanyl-related substances on Schedule I started in 2018, yet fentanyl continued to spread for years and now accounts for the vast majority of overdose deaths. In fact, experts worry that cracking down on xylazine will simply trigger the “iron law of prohibition”—which asserts that supply-side crackdowns incentivize the manufacture and sale of increasingly potent substances—and could drive the proliferation of even more dangerous drugs like medetomidine and nitazenes (which has already begun in some states).

Beyond increasing the toxicity of the illicit drug market, a rush to schedule ahead of the science could place xylazine on too restrictive of a schedule. This would unnecessarily hinder the very research that can help get us out of the overdose crisis through development of targeted antidotes or more effective treatments. And because xylazine has not historically been used in humans, there is much to learn. In fact, a recently published study found that xylazine might respond better to naloxone than previously suspected. This type of information could save lives; making it harder to discover will not. In addition, while drugs can be downscheduled, the process to do this is neither quick nor simple and could further slow scientific discovery. Cannabis is a contemporary example of the herculean effort required to do so.

Thus, before scheduling xylazine, we urge the government to engage in the appropriate science, to be transparent with their findings and recommendations, and to seriously consider the potential benefits and harms associated with any scheduling decisions. The responsibility of drug scheduling, whether through relevant agencies or Congress, should follow research.