Comparison of Intravenous Ketamine with Morphine in Pain Relief of Long Bones Fractures: a Double Blind Randomized Clinical Trial

INTRODUCTION The selective medication for pain control in many clinical situations is morphine but its complications prevent its widespread use. Ketamine has been introduced as an alternative for morphine in some studies. However, the efficacy of its solitary use has not yet been evaluated. Therefore, the present study was undertaken to evaluate the effect of ketamine alone in relieving pain in trauma patients referring to an emergency unit. METHODS In this double-blind clinical trial, patients with long bone fractures were randomly divided into two groups of treatment with intravenous (IV) morphine at a dose of 0.1 mg/kg and treatment with IV ketamine at a dose of 0.5 mg/kg. Pain severity of the patients was recorded before and 10 minutes after injection based on numeric rating scale. The means in the two groups were compared using independent t-test. Then the Kaplan-Meier curve and log rank analysis were used to evaluate the success of treatment. RESULTS 126 patients were included in this study. The mean ages of the patients in the morphine and ketamine groups were 33.6±14.3 and 35.1±13.5 years, respectively (P=0.54). After therapeutic intervention, the pain severity significantly decreased in ketamine (2.7±1.8; P<0.0001) and morphine (2.4±1.5; P<0.0001) groups, with a similar effect of both medications on alleviating pain (P=0.28). The success rate of the treatment at 10-minute interval in groups receiving ketamine and morphine were 59 (93.65%) and 61 (96.8%) patients, respectively (P=0.62). CONCLUSION The results of the present study showed that administration of ketamine at a low dose (0.5 mg/kg) results in a significant decrease in the severity of acute pain in patients with fractures of long bones. This palliative effect is very similar to that of morphine.