HO-1 is induced by various stresses, including oxidative stress and ischemia reperfusion stress.11,13 The HO-1 inducer cobalt protoporphyrin IX (CoPP) and the CO-releasing molecule tricarbonyldichlororuthenium (II) dimer (CORM-2) have been shown to enhance the analgesic effects of opioid analgesics in neuropathic pain.6–8 However, the effects of HO-1 on the analgesic effects of gabapentinoids are unknown. This evidence concerns the gene HMOX1 and neuropathic pain.