Tramadol Offers Pain Relief for Postherpetic Neuralgia

Treating postherpetic neuralgia patients with the oral opioid agonist tramadol may significantly reduce moderate to severe nerve pain, according to one study published in the April 2013 issue of Pain Practice.

In their “A Randomized, Prospective Study of Efficacy and Safety of Oral Tramadol in the Management of Post-Herpetic Neuralgia in Patients from North India” clinical investigation, Ashok K. Saxena, MD, DA, FAMS, of the Department of Anesthesiology and Critical Care in the University of Delhi’s College of Medical Sciences, in India, and colleagues evaluated the efficacy and safety of the central nervous system drug tramadol hydrochloride — which is trademarked as Ultram, Ultracet, Ryzolt, and ConZip in the US — in 100 outpatients with postherpetic neuralgia.

All participants received 50-milligram to 200-milligram daily doses of oral tramadol therapy for four weeks. After 14 days, those who achieved at least 50 percent pain relief were categorized as responders, while those who reported less than 50 percent pain relief were grouped as non-responders. In addition to their tramadol regimen, participants in both groups received topical rescue analgesia in a cream form of 3.33 percent doxepin and 0.05 percent capsaicin on their affected areas of postherpetic neuralgia for at least 14 days; however, it was extended to four weeks in the non-responder group.

After 28 days of treatment, the researchers compared the two groups on the basis of pain intensity scores measured with a Numerical Rating Scale (NRS) at rest and with movement, global perceived effect (GPE), Neuropathic Pain Symptom Inventory (NPSI), and daily sleep interference (DSIS), as well as on the basis of quality of life (QOL) scores measured with the WHO QOL-BREF Questionnaire and patient and clinician ratings of global improvement.

The investigators found NPSI, DSIS, and resting and movement NRS scores “were consistently reduced (P < 0.001) over 28 days at varying intervals in both the groups, but the magnitude of reduction was higher in responders than non-responders.” Similar results were observed in the QOL scores, as the researchers wrote that “although the WHO QOL-BREF scores showed significant (P < 0.001) improvement in QOL of (postherpetic neuralgia) patients at days 14 and 28 in both groups, the magnitude of improvement was higher in responders as compared to non-responders.”

Though the researchers concluded the tramadol treatment resulted in “significant pain reduction in terms of enhanced pain relief, reduced sleep interference, greater global improvement, diminished side-effect profile, and improved QOL in (postherpetic neuralgia) patients,” they noted the pain intensity and QOL improvements in the non-responder group was “mainly attributed to the use of rescue analgesia for 28 days, rather than recommended tramadol therapy.”

“Further categorization of (postherpetic neuralgia) patients may be helpful so that additional or alternative therapy may be prescribed to non-responders,” the authors wrote.