Antidepressant may ease pain experienced by patients in chemotherapy

Chemotherapy is used to kill cancer cells in the body, but it can also cause a lot of nasty side effects, including nausea, hair loss, fatigue and pain.

A new study suggests that giving people who are undergoing chemo a commonly-prescribed antidepressant may alleviate pain in these patients.

Between 20 and 40 percent of patients with cancer who receive chemo as treatment experience a condition called chemotherapy-induced peripheral neuropathy (CIPN), according to the new study's authors.

This condition describes a set of symptoms caused by damage to nerves in the body. The nerves, called peripheral nerves, are found further away from the brain and spinal cord, and are responsible for sensations and movements in areas such as the arms and legs, according to the American Cancer Society.

Symptoms may include shooting or stabbing pains, burning, "pins and needles" tingling, numbness, balance problems and sensitivities to temperatures, mostly cold. The society adds that people with the condition may experience pain so severe it interferes with their ability to perform everyday actions like walking, writing and getting dressed. People with severe cases may also experience dangerous changes in heart rate and blood pressure, severe falls, breathing problems, paralysis or organ failure.

The researchers, led by Dr. Ellen M. Lavoie Smith, a CIPN expert at the University of Michigan School of Nursing, Ann Arbor, conducted a clinical trial with 231 patients ages 25 and older who were treated with chemotherapy between 2008 and 2011, and experienced pain. They wanted to confirm earlier trials that found antidepressants like duloxetine (brand name Cymbalta) may reduce pain symptoms.

The researchers randomized  patients to receive either the antidepressant followed by a placebo treatment, or vice versa, and followed-up with them to gauge their pain on a scale of one to ten.

Patients treated with duloxetine first reported a larger decrease in pain scores -- about a one point drop -- compared to those treated with a placebo first.

Smith told HealthDay that was a "clinically significant" change that would have a measurable effect on patients daily lives.

Fifty-nine percent of them reported a decrease in pain compared to 38 percent of the patients treated with a placebo first. Thirty percent of patients treated first with duloxetine, however, saw no drops in pain, while 10 percent experienced increased pain.

"Five weeks of duloxetine treatment was associated with a statistically and clinically significant improvement in pain compared with placebo," the researchers concluded in the study, published April 2 in JAMA.

By further breaking down participants by type of chemotherapy drugs they were on, the researchers found those treated with platinum chemotherapy drugs (oxaliplatin) experienced the greatest pain relief with the help of duloxetine, compared to those treated with taxane chemo drugs.

Marie Bakitas, an oncology professor at the University of Alabama at Birmingham School of Nursing who was not involved in the research, told Medscape the findings did not surprise her based on what she's seen in patients.

"Duloxetine is being used in clinic now, and it is clearly an efficacious drug," she said. "This study is key because it provides the evidence needed to support practice."

Dr. Michael Stubblefield, who treats patients with CIPN at Memorial Sloan-Kettering Cancer Center in New York City and was not involved in the study, pointed out that not everyone in the study responded to duloxetine.

This doesn't mean I'll be putting all my patients on it," he told HealthDay.