Does Zohydro ER help people with long-term pain?

Prescription opioids claim the lives of more than 16,000 people each year in the U.S., and send nearly half a million people to the emergency room, according to the Centers for Disease Control and Prevention (CDC). In more than half of cases, people got their prescriptions from their regular doctor.

Zohydro ER (hydrocodone) is one of five narcotic pain drugs approved for sale by the Food and Drug Administration since late 2013. The other four are Embeda (morphine and naltrexone), Hysingla ER (hydrocodone), Targiniq ER (oxycodone and naloxone) and Xartemis XR (oxycodone and acetaminophen).

Those five drugs are long-acting opioids, meant to treat moderate-to-severe long-term pain in people who need round-the-clock relief. Narcotic pain drugs are essential to help treat severe, short-term pain from, say, surgery, and can also help with longer-lasting pain from cancer or a terminal illness. But the drugs can also be addicting and pose other serious risks, including a risk of overdose and death.

Read more about the dangers of pain killers.

That's why we commissioned Lisa M. Schwartz and Steven Woloshin, both physicians and professors at Dartmouth's Institute for Health Policy and Clinical Practice at the Geisel School of Medicine, to review the evidence that the FDA relied on when the agency approved Zohydro ER back in October 2013.

When drug companies apply for approval of a new drug, they must submit research showing that the drug is safe and effective. In some cases, the FDA asks an independent committee of experts to review the studies and vote their opinion. We took a closer look at Zohydro ER because this committee voted 11 to 2 against approval of the drug (you can read the meeting transcripts). For the other four drugs, no such committee meeting to review the study evidence was held, although a summary of the research is publicly available.

The FDA primarily used one study on how well Zohydro ER works to approve the drug and it was published in the medical journal Pain Medicine in 2014. It included about 300 adults with chronic back pain who were already taking opioid pain relievers.

Here's how the study worked: First, everyone took Zohydro ER for six weeks. Then researchers had some people continue to take the drug while other people were switched to a sugar pill (placebo) for three months. The people in the study didn't know if they were taking Zohydro ER or the sugar pill, and neither did their doctors. If someone in the study had pain that was particularly bad, they were allowed to take a different, short-term opioid pain drug whenever they needed.

In our analysis, Schwartz and Woloshin took that study and summarized it in an-easy-to-understand Drugs Fact Box. It's similar to the Nutrition Facts on packaged foods. It shows that Zohydro ER did not help much to relieve pain or help people move around easier during their day-to-day activities.

How well did Zohydro ER work?

Every day, people in the study were asked to rate how severe their pain was. At the end of the study when those ratings were averaged together, they showed that people who took Zohydro ER felt only slightly better than those who took a sugar pill. People who took Zohydro ER also reported that the drug didn't help them function much better.

Surprisingly, if people took Zohydro ER, it did not reduce their need to take other pain relievers to treat flare-ups of pain. Both people who took Zohydro ER and those who took a placebo wound up taking additional pain medications about 7 out of every 10 days.

Also, the study found that about one-third of people who took a placebo pill instead of Zohydro ER experienced at least moderate pain relief.

Zohydro ER's side effects

Some people who took Zohydro ER said it caused them side effects, including constipation, nausea, vomiting, stomach pain, or headache, which are typical of all opioid drugs. Some people who took the sugar pills also experienced some of those side effects, although generally not as often.

Unfortunately, one person died during the study after taking an overdose of Zohydro ER and other opioid medications, which underscores the danger of misusing these powerful drugs.

Schwartz says because the drug is new and has only been studied in a small group of people, she worries that more serious side effects may surface when more people use it over a long period of time. "Unfortunately, at this point, the long-term safety and benefits are unknown," she says.

Weighing risks and benefits

Some medical experts say that the evidence the FDA reviewed wasn't strong enough to show that Zohydro ER is a safe and effective way to treat back pain, or other forms of long-term pain that is not caused by cancer or a terminal illness.

The FDA committee that reviewed the data on Zohydro ER also said it was concerned that people could abuse or misuse the drug. This was because it was not originally formulated to make it harder to abuse. (However, just recently, the FDA approved a new formulation of the drug that should discourage people from abusing it to get high.)

The FDA approved the original version of Zohydro ER anyway. And the agency highlighted new rules it created for the entire class of these opioid drugs as ways to reduce risk for people who took the drugs. The new rules require stronger warnings on labels and that drug manufacturers make education available to health care providers who prescribe the drugs.

The agency also pointed out that abuse-deterrent technology has not been perfected. The technology makes it harder for people who intentionally abuse opioids to tamper with the pills—by, for example, crushing or dissolving them so that they can snort or inject the entire extended-release dose all at once. Embeda, Hysingla ER, Targiniq ER, and Xartemis XR are formulated to be hard to tamper with.

Unfortunately, the hard truth is that growing evidence suggests none of the drugs in this class are safe or very effective when used long term against many forms of chronic pain.

One recent statement by the American Academy of Neurology this past September underscores this issue: The professional association officially warned its physicians about the use of opioids for non-cancer chronic pain such as back pain, frequent headaches, or fibromyalgia, stating that the risk of death, overdose, addiction or other serious side effects likely outweigh any potential benefit.

"The science on the treatment of chronic pain is evolving.  Right now, we do not have evidence that people who take around-the-clock opioids for chronic non-cancer pain over the long-term function better or have better quality of life. It does not make sense to add more—and possibly more dangerous—opioids to the list until their long-term benefit and safety are proved," Woloshin says.

Learn five surprising facts about prescription painkillers.

Proponents say that Zohydro ER as well as another newly approved narcotic, Hysingla ER, may be safer for some patients because they contain hydrocodone alone and are not combined with acetaminophen (the active ingredient in Tylenol) like Vicodin and other popular narcotic prescription painkillers. Acetaminophen, while safe for most people if used as directed, can damage your liver if you take too much.

But like the FDA advisory panel, our experts remain unconvinced that the absence of acetaminophen makes Zohydro ER a substantially safer opioid. While liver failure is an important issue, about 20 times more people die as a result of overdose from opioids than from acetaminophen according to the CDC.

Instead, one of the most important recent safety measures taken by the U.S. Drug Enforcement Agency was to tighten the restrictions on prescribing Vicodin and other hydrocodone-combination drugs, some of the most commonly prescribed drugs in the U.S. We also applaud the FDA's move to reduce the maximum dose of acetaminophen in prescription drugs to 325 milligrams per pill and hope they will act soon to do the same for over-the-counter products. Acetaminophen is a significant culprit behind liver failure in the U.S., and nonprescription products account for 80 percent of the drug taken in this country.

Bottom line: Few conditions are as frustrating as debilitating long-term pain. Unfortunately, for most sufferers, opioids don't provide much relief and subject them to potentially too much risk of harm.

"People who suffer from chronic pain should try to find a good team of people with expertise in dealing with the condition to make sure that other medications and nondrug options have been given a chance to work before resorting to round-the-clock narcotics," Schwartz advises.