Some chemotherapy medications can cause peripheral neuropathy - a tingling feeling which is usually felt in the toes, feet, fingers and hands. For some patients the sensation is just uncomfortable - but for approximately 30%, there is unpleasant pain.
The researchers explained that prior studies were unable to find any reliable way to treat chemotherapy-induced peripheral neuropathy.
Ellen M. Lavoie Smith, Ph.D., APRN, AOCN, and team examined 231 patients who had received paclitaxel and oxaliplatin, both chemotherapy drugs, and had reported painful neuropathy afterwards. They were randomly selected to receive either Cymbalta or a placebo for five consecutive weeks. Throughout the 5-week period the participants were asked to describe their pain.
59% of those on Cymbalta reported reduced pain, compared to 39% on placebo.
Dr. Smith said:
"These drugs don't work in everyone. The good news is it worked in the majority of patients. We need to figure out who are the responders. If we can predict who they are, we can target the treatment to the people it's going to work for."
Duloxetine, which experts say works by increasing neurotransmitters that block pain signals to the brain, had been shown in previous study to help diabetes patients with painful neuropathy.
The participants were given 30 milligrams of duloxteine per day during the first week, and then 60 mg per day for the subsequent four weeks. By gradually increasing the dosage, the researchers believed there would be fewer side effects.
The most common reported side effect was fatigue.
If a doctor can effectively treat a patient's painful neuropathy, their chemotherapy dose does not have to be reduced, the researchers explained.
Dr. Smith said "In addition to improving symptoms and quality of life, treating peripheral neuropathy pain potentially improves quantity of life if it helps patients avoid decreasing their chemotherapy medications."
It is not uncommon for patients to suffer painful peripheral neuropathy in silence because they do not want the doctor to reduce their chemotherapy dosages.
Smith said "Patients make this trade-off sometimes: They don't want to give up the chemotherapy and decide they'd rather have this pain. That's a terrible trade off to make."
Smith and team say they now want to find out which patients are likely to benefit the most from Cymbalta.