An approved medication, Cymbalta (duloxetine) is effective at easing pain in fibromyalgia (FM) patients, a large meta-analysis shows. A daily 60 mg dose is enough to trigger therapeutic benefits with a lesser risk side effects than is likely at higher doses.
The study “Duloxetine for pain in fibromyalgia in adults: a systematic review and a meta – analysis” was published in the International Journal of Neuroscience.
Although the mechanisms behind FM are not completely understood, the disease is known to be linked with problems in neurotransmitters — chemicals that transmit nervous signals — that play a role in processing pain and the response to stress.
Cymbalta, originally indicated to treat depression, is also approved in the U.S. and elsewhere to ease pain linked to fibromyalgia and promote overall well being. The medicine increases the levels of the neurotransmitters serotonin and norepinephrine that help relieve pain and depression. Its dose use in clinical practice ranges from 30 up to 120 milligrams (mg) a day.
A team of researchers in China performed a systematic analysis of studies published from 2000 through March 2019 to evaluate the analgesic (pain-easing) efficacy of Cymbalta. They also assessed whether a dose of 60mg/day or 120mg/day of Cymbalta was most effective.
The researchers analyzed data from seven clinical studies evaluating Cymbalta in a total of 2,642 FM patients, with a mean age of 49 to 51. All the seven studies were randomized trials with a placebo control group.
Their analysis showed that patients taking Cymbalta had a significantly higher probability of having at least 30% or 50% pain relief compared to those in placebo groups. This was accompanied by a significant patient global impression of change or improvement.
Cymbalta treatment was also linked to side effects that included nausea (most frequent), constipation, hyperhidrosis (excessive sweeting), headache, dry mouth, sleepiness, and insomnia. About 82% of patients on Cymbalta and 70% in the placebo groups experienced one adverse event. Serious side effects were rare, seen in 1.8% of patients using Cymbalta and in 2.2% in those given a placebo, the study said.
In total, 15.5% of patients on Cymbalta stopped treatment due to side effects compared to 9.5% of placebo patients.
But fewer people in Cymbalta group ( 5.1%) stopped treatment due to lack of efficiency than in the placebo group (9.7%), supporting the anti-depressant’s effectiveness for easing pain and managing depression.
Analysis also revealed that the 60 mg daily dose was preferable to the higher 120 mg dose per day. A daily dose of 60 mg was linked to fewer side effects and a lower rate of withdrawal.
“There was no need to increase the dose in treating FM and it might be concluded that 60mg/d DLX [duloxetine] was more suitable for FM patients” the researchers wrote.
Overall, “DLX [duloxetine] was a great choice for pain relief in FM,” and the “60mg/d DLX produced less withdrawal effects than 120mg/d DLX,” the study concluded.