Background Numerous drugs have been proposed to alleviate ischaemic limb pain, but none have been successful in relieving ischaemic pain thoroughly and rapidly.

Objective To compare the effectiveness of intravenous lidocaine and intravenous morphine in decreasing pain in patients with critical limb ischaemia.

Methods A randomised double-blind controlled trial was performed in 63 patients with critical limb ischaemia recruited from the emergency department between October 2012 and December 2013; 23 patients were excluded and the remainder were randomly divided into two groups of 20 patients. Patients in the lidocaine group received lidocaine infusion (2 mg/kg) while patients in the morphine group received morphine (0.1 mg/kg). Patients’ visual analogue pain scores (VAS), from 0 to 10, were reported before and 15 and 30 min after the infusion.

Results Before the infusion the mean±SD VAS score was 7.50±1.93 in the lidocaine group and 7.65±1.92 in the morphine group. At 15 min the mean±SD VAS score in the lidocaine group was lower than in the morphine group (5.75±1.77 vs 7.00±1.83; mean difference 1.25, 95% CI 0.095 to 2.405) and, at 30 min, the mean±SD VAS score in the lidocaine group was again lower (4.25±1.48 vs 6.50±1.73; mean difference 2.25, 95% CI 1.218 to 3.282).

Conclusions Lidocaine may be helpful in decreasing ischaemic pain in patients with critical limb ischaemia.

Trial registration number http://www.irct.irIRCT201210148872N2.