Researchers from Queen’s University in Kingston, Ontario, have found that an anti-seizure drug gabapentin and an antidepressant nortriptyline taken together is a more effective treatment to stop the pain of post-herpetic neuralgia (PHN) than either of the medications alone.
While patients sometimes get pain relief from morphine and other of the strongest pain relievers, the Queen’s team says a better option might come from combining the gabapentin and nortriptyline.
Dr. Ian Gilron, director of Clinical Pain Research for Queen’s Departments of Anaesthesiology, and Pharmacology & Toxicology and an anaesthesiologist at Kingston General Hospital, found that not only do patients report pain relief, they also report better sleep – something not seen in morphine treatments.
“That’s a very important issue for this group of patients, whose debilitating, unrelenting pain often interferes with normal sleep,” Gilron said in a news release, announcing the study’s findings which are published in The Lancet.
Each of the drugs has been recommended for neuropathic pain relief on their own. However, the drugs rarely reduce pain by more than 60 per cent and only about half of patients find they work at all, in part because the dosages have to be capped because they carry serious side effects at high doses.
But Gilron found that taking both at once allowed more people to report relief. In his randomized controlled trial, he tried the combo on 56 patients with diabetic neuropathy or postherpetic neuralgia (the chronic pain from shingles). All these patients reported their daily pain as at least a 4 on a scale of 0 to 10 before they started the trial.
There were three daily treatment plans: gabapentin, nortriptyline, or their combination. All patients got to try all three treatments over three 6-week periods. Overall, more people reported good pain relief when the drugs were combined:
• 64 per cent reported moderate to complete relief with gabapentin
• 75 per cent reported moderate to complete relief with nortriptyline
• 81 per cent reported moderate to complete relief with the combination.
There were few side effects from the combination, though some complained of dry mouth.