A single infusion of intravenous ketamine improves pain relief in patients with critical limb ischaemia: results of a double blind randomised controlled trial

Pain. 2002 Jun;97(3):275-281. doi: 10.1016/S0304-3959(02)00033-7.


We report the first double blind randomised controlled trial of regular opioids and an infusion of low dose (0.6 mg/kg) intravenous ketamine compared with opioids and placebo in patients with allodynia, hyperalgesia and hyperpathia secondary to critical limb ischaemia. Thirty-five patients completed the study, 18 received regular opioids plus ketamine, while 17 received regular opioids plus placebo. Using the Brief Pain Inventory, the % pain relief that the patients in the ketamine group attributed to their medication improved significantly from 50% immediately pre-infusion to 65% 24 h post-infusion and 69% 5 days post infusion. Over the same period, the pain relief achieved by the placebo group rose from 58% pre-infusion to 56% 24 h post infusion and then 50% relief 5 days later. This was statistically significant (P<0.05) using both the t-test and the Wilcoxon Rank Sum test. The ketamine group also showed a statistically significant difference 24 h post infusion of the effect of pain on their general activity (P=0.03) and on their enjoyment of life (P=0.004). This study shows that combining a single infusion of low dose ketamine with regular opioid analgesia can result in a significant improvement in pain relief for this patient group.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Analgesics / administration & dosage*
  • Analgesics / adverse effects
  • Analgesics, Opioid / administration & dosage
  • Anxiety / drug therapy
  • Depression / drug therapy
  • Double-Blind Method
  • Extremities
  • Female
  • Humans
  • Infusions, Intravenous
  • Ischemia / complications*
  • Ketamine / administration & dosage*
  • Ketamine / adverse effects
  • Male
  • Pain / drug therapy*
  • Pain / etiology
  • Treatment Outcome


  • Analgesics
  • Analgesics, Opioid
  • Ketamine