Pregabalin and gabapentin for the treatment of sciatica

• Pregabalin (PGB) and gabapentin (GBP) are both used to treat neuropathic pain, but their precise role in sciatica has been under-explored.
• The amount and quality of evidence for their use is low.
• Weak evidence suggests efficacy and side effect profiles of PGB and GBP in sciatica are similar.
• The rulings of formulary regulators in individual countries are disparate: most favour PGB over GBP.

Whilst pregabalin (PGB) and gabapentin (GBP) are both used to treat neuropathic pain, their relative role in sciatica is unclear. Our aim was to extensively review the roles of PGB and GBP in treating sciatica. The efficacy, side effects (SE) profile and cost of PGB and GBP in neuropathic pain states were reviewed with special reference to sciatica. Eleven articles matched the criteria: seven systematic reviews, one retrospective cross-sectional study, one placebo-controlled-crossover study, one randomized placebo-controlled double-blind study and one case report. GBP and PGB appeared to demonstrate comparable efficacy and SE. However, the amount and quality of evidence was low, and only indirect comparisons were available. Importantly, no direct “head-to-head” study existed. Globally, costs varied widely (by up to 31 times) and unpredictably (PGB cheaper than GBP, or vice versa). Formulary regulator rulings were globally disparate; however, many exclusively favoured the more expensive drug (whether GBP or PGB). No studies assessed PGB-GBP interchange. Weak evidence suggests that efficacy and SE with GBP and PGB are probably similar; however, firm conclusions are precluded. Despite weak data, and having cited minor titration, but definite cost, advantages, UK National Institute for Health and Clinical Excellence favoured PGB over GBP. Given that no evidence supports unhindered PGB-GBP interchange, neither drug should probably be favoured. Prospective “head-to-head” studies are urgently required to provide robust evidence-based knowledge for choice of GBP or PGB in sciatica.