Methadone Linked to Initial QTc Prolongation in Chronic Pain
Nonsignificant increase in QTc in first month after initiating methadone, which does not persist
FRIDAY, June 26, 2015 (HealthDay News) -- For patients with chronic pain, methadone is associated with a small, but nonsignificant, initial increase in QTc, which does not persist, according to a study published in the June issue of Pain Medicine.
Samuel Grodofsky, M.D., from the University of Pennsylvania in Philadelphia, and colleagues conducted a prospective cohort study in a chronic pain clinic involving 82 patients receiving methadone and 102 receiving non-methadone opioid therapy. Automated QTc calculations from 12-lead electrocardiograms were analyzed at baseline and during the subsequent six months.
The researchers found that there was no overall higher frequency of QTc >470 milliseconds in the methadone group (6 percent for methadone group versus 5 percent for controls; P = 0.722). Furthermore, the methadone group had no increase in the incidence of QTc >60 milliseconds from baseline (4 and 4 percent, respectively; P = 0.94). Patients in the methadone group exhibited an increase in QTc compared with controls in the first month after initiating methadone (5 versus 0 percent; P = 0.073), but the difference did not persist at three and six months.
"We believe larger scale studies to further characterize the safety profile of low-dose methadone are warranted," the authors write.