Journavx: How Safe Is This New FDA-Approved Painkiller?

On January 30, 2025, the Food and Drug Administration (FDA) approved a new drug for short-term pain relief, with both the agency and its manufacturer claiming it carries no risk of addiction. But is Journavx (suzetrigine) the opioid substitute we’ve been waiting for?

Harold Hong, M.D., a psychiatrist and medical director of New Waters Recovery, says Journavx “may be beneficial for patients at high risk of addiction,” including those with a history of substance use disorder or individuals avoiding opioids due to the risks. He adds that older adults and people with respiratory conditions—who face higher risks of opioid-related complications—could also benefit from this “safer alternative.” 

However, “since this drug is still new,” Dr. Hong cautions that more long-term data is needed to fully understand its safety profile.

Here’s what you need to know about the efficacy and side effects of Journavx, the new painkiller that experts hope will reduce America’s dependence on opioids.

How Journavx Works

When you experience pain from an injury or after surgery, nerve cells in the affected area send signals to your brain, alerting it to the distress. Opioids, a class of drugs commonly used for pain relief, work by binding to specific surface molecules on the cells in the brain and spinal cord as well as throughout the body, that block these signals, reducing the sensation of pain.

Journavx works by blocking a sodium channel, NaV1.8, that is only expressed on nerve cells that sense pain in our bodies. These cells are part of our peripheral nervous system, meaning they’re found in the muscles and nerves throughout the body, but not in the spinal cord or the brain.

“This means it targets pain at its source rather than altering how the brain perceives pain like opioids do,” says Dr. Hong. “Since it does not interact with the brain’s reward system, it does not come with the same risk of addiction,” he continues.

Inside the Clinical Trials: How Journavx Was Tested

Journavx received a breakthrough therapy designation, fast track and priority review from the FDA, which allowed it to be evaluated and approved faster and with more guidance from the FDA than the average drug because it was expected to be safer than existing pain medications.

The drug’s January approval was based on the combined results of two phase 3 clinical trials that included a total of 2191 participants.

In the trials, participants who had either foot or abdominal surgery took Journavx, an opioid-acetaminophen combination, or a placebo for two days. Participants who took Journavx reported greater pain relief than those on a placebo, but not more than those  taking an opioid-acetaminophen combination pill.

A third trial mentioned in the FDA approval announcement tested the drug on 256 individuals who had pain for a variety of reasons, though most (222 people) had pain related to surgery. In this study, all participants used Journavx — there were no placebos or alternative treatments—for up to 14 days. The purpose of this trial was to identify any safety concerns with the medication. The most common adverse effect was headache, which 7% of participants reported.

Because these trials only tracked participants for the short duration, “We can’t necessarily have an assurance about its long-term effect,” says Mitchell McDowell, D.O., an orthopedic surgeon in California. The company is now conducting longer trials to evaluate Journavx for chronic pain, but those results are not yet available.

It’s also worth noting that the FDA prescribing information highlights that the majority of trial participants were white females, and the company did not have enough data to break down outcomes among individuals of different sexes, ethnicities or ages.

Side Effects of Journavx

According to the FDA’s approval announcement, the most common side effects of Journavx in its limited clinical trials included:

• Itching
• Muscle spasms
• Elevated blood levels of creatine phosphokinase (which can signify muscle damage or even seizure or brain trauma, though those experiences were not reported by any study participants.)
• Rash

These effects occurred in about 1.1-2.1% of those who took Journavx.

Nausea and vomiting were common among all participants in the trials, regardless of whether they were given Journavx, the opioid-acetaminophen combination or a placebo, so this side effect was likely caused by the procedure or anesthesia participants underwent, as opposed to the pain medication.

Additionally, about 2.5% of trial participants who took Journavx experienced reduced kidney function (based on laboratory tests). The researchers did not conduct long-term follow-ups on individuals who took the drug for only two days, so it remains unclear how quickly they recovered. However, among those who used the drug for 14 days, kidney function naturally returned to normal, and no patients reported symptoms of kidney problems.

Still, the potential for kidney dysfunction concerns Dr. McDowell. He’d like to see more details on the elevated kidney enzymes observed in trials — including their timing, severity, and how quickly they returned to normal. In December 2023, before Journavx was FDA approved, Vertex released data from a 12-week phase 2 study in people with diabetic nerve pain, and found that about 5% of participants showed signs of reduced kidney function in lab tests. However, results from larger phase 3 trials aimed at demonstrating that Journavx is safe and effective for long-term use are still pending. If those trials demonstrate positive results, the company will apply for the drug to be approved for use to treat chronic pain.

How Other Drugs Interact with Journavx

Many drugs—including calcium channel blockers, benzodiazepines, and even certain supplements like St. John’s Wort and foods like grapefruit—are processed by an enzyme in the body called CYP3A. When multiple substances that rely on CYP3A are taken together, they can interfere with how the enzyme works. This interference can alter how quickly a drug is broken down and leaves the body, potentially affecting its effectiveness or safety. Since Journavx is also processed by this enzyme, it’s important to discuss all medications and supplements with your doctor to avoid unintended interactions.

Additionally, Journavx can reduce the effectiveness of some birth control methods, especially those with certain progestins, during treatment and for 28 days after. Using backup contraception, like condoms, is recommended during this time.

What We Still Don’t Know about Journavx

Now that the FDA has approved Journavx, its widespread use may reveal additional side effects, particularly among a more diverse patient population beyond the primarily white women included in the trials.

Additionally, no currently published clinical trials include data on individuals taking the drug for more than 14 days. Over time, longer studies and real-world data will tell us more about how the drug affects people long-term.

“The good news is that Journavx does not work like opioids — it does not activate the brain’s reward system, so it should not lead to dependence in the way traditional painkillers do,” says Dr. Hong. “That said, we need more real-world data to see how patients use it outside of controlled clinical trials. Some people may try to take higher doses, hoping for more potent pain relief, and we need to ensure it is truly safe in all scenarios.”