Overdoses involving gabapentinoids alone are uncommon because they require consumption at up to 25 times the maximum recommended dose. Moreover, these overdoses are rarely fatal.
“You almost can’t overdose on a gabapentinoid, because you have to take lots and lots of it to do so, and you’ll usually survive. But if you add it to an opioid or other sedative, then you’re really in dangerous territory. That’s where all the deaths are clustered,” Dr. Walley explained.
A recent Canadian/Dutch population-based, nested, case-control study concluded that concomitant prescription of opioids and gabapentin was associated with a 49% greater chance of fatal overdose, compared with opioid prescription alone, in an analysis extensively adjusted for potential confounders. A dose-response effect was noted, such that coprescription of high-dose gabapentin was linked to an adjusted 58% increased risk (PLoS Med. 2017 Oct 3;14[10]:e1002396).
Complicating the picture, however, is solid evidence from a randomized, placebo-controlled, crossover trial that gabapentin and opioids are synergistic for relief from neuropathic pain, which can be notoriously difficult to control (N Engl J Med. 2005 Mar 31;352[13]:1324-34).