Studies Presented at APS Highlight Fast Onset of Pain Reduction and Potential Opioid-sparing Effect in Patients Treated with Once-daily Gabapentin for Postherpetic Neuralgia

Pain Management, May 2012, Volume 5, Issue 3

A summary of trials involving patients treated with once-daily gabapentin.

The authors of “Effect of a once-daily gastroretentive formulation of gabapentin on the Brief Pain Inventory Scale scores in patients with postherpetic neuralgia” (http://bit.ly/KvtBWL) reported that patients treated with once-daily gabapentin 1800 mg for eight weeks (preceded by a two-week dose titration period) experienced improvements in all five pain scores measured by the BPI (worst, least and average pain in previous 24 hours, present pain, and percent relief). They also experienced significant improvements in measures of sleep and enjoyment of life, as well as borderline improvements in mood.

In “Use of opioid analgesics in patients with postherpetic neuralgia (PHN) first treated with gabapentin or pregabalin” (http://bit.ly/L6oIc8), researchers looked at the frequency of newly initiated opioid therapy in patients who were previously treated with gabapentin or pregabalin for postherpetic neuralgia (PHN). Using claims data for 1,645 patients (939 gabapentin, 706 pregabalin), they found that 21.2% of patients taking gabapentin and 17.9% of patients taking pregabalin were also prescribed opioids within 12 months of initiating therapy. Interestingly, researchers found that the average daily doses of gabapentin and pregabalin received by these patients were below the FDA-approved maximum dosage for these medications, leading them to speculate that “it is possible that if patients in community practice were titrated to higher and potentially more effective dosages of gabapentin or pregabalin, use of opioid analgesics in PHN might be reduced.”

The authors of “Onset of treatment response to a once-daily gastroretentive formulation of gabapentin in patients with postherpetic neuralgia” (http://bit.ly/IOJhu3) analyzed onset of treatment response (defined here as the first of two consecutive days with significantly greater reduction in Numeric Pain Rating Scale scores from baseline) in patients treated with once-daily gabapentin 1800 mg for eight weeks (preceded by a two-week dose titration period). They reported that patients treated with once-daily gabapentin experienced “significantly greater pain reduction” as early as two days after initiating treatment, compared to patients who received placebo. Reduction in pain scores continued for about 45 days and remained “statistically greater” in the gabapentin group for the duration of the 10-week study, compared to the placebo group.