Antidepressant Lessens Chemo-Related Pain
Cymbalta shows positive effect on neuropathy in clinical trial
The study included 231 patients with nerve pain that had persisted for at least three months since their chemo regimen ended. Half were randomly assigned to take Cymbalta for five weeks, while the other half took placebo pills. The two groups then switched treatments. None of the patients knew when they were taking the real drug and when they were on the placebo.
Of the patients given Cymbalta first, the average pain score fell by a point on a scale of 0 to 10. That's considered to be a "clinically important" change, Smith said, meaning it's an improvement patients notice in their daily lives.
The Cymbalta patients were also twice as likely to have a 50 percent decrease in pain scores versus the placebo users, and overall they reported improvements in their daily functioning and quality of life.
It is not clear how the antidepressant helps with nerve-related pain, but it is thought to act on certain brain chemicals involved in transmitting pain signals.
The findings are encouraging, Stubblefield said. But, like Smith, he pointed out that not everyone responds to Cymbalta. "This doesn't mean I'll be putting all my patients on it," he said.
There are other treatments for chemo-related pain -- although they have not yet been shown to work in rigorous clinical trials. One option, Stubblefield said, is Lyrica (pregabalin), which is another drug approved to treat other forms of nerve-damage-related pain.
Stubblefield said Lyrica tends to have fewer side effects than Cymbalta, and at least some patients may be able to tolerate it better. Cymbalta's side effects include fatigue, insomnia and nausea, which were reported by 5 percent to 7 percent of patients in the current study.
On the other hand, Stubblefield said, if a patient with nerve pain is also feeling depressed, it makes sense to try Cymbalta first.
There's also cost. Cymbalta is not yet available as a generic, and runs close to $200 a month. It is scheduled to lose patent protection at the end of 2013, so cheaper versions may become available.
Smith said there are still many questions to sort out: How well can patients tolerate Cymbalta over a longer term? Does the drug help nerve pain in patients who are still on chemo?