Comparison of the effect of intravenous fentanyl with low-dose ketamine on pain relief in patients taking methadone and suffering from limb fractures

Given the significance of pain control in addicted patients and the prominence of not using opioids due to patient’s drug dependence, the present study aimed at comparing and evaluating the effect of intravenous fentanyl with low‑dose ketamine on pain relief in patients taking methadone and suffering from limb fractures.

The present double‑blind randomized clinical trial was performed on 100 patients taking methadone and suffering from limb fractures. The patients were divided into two groups receiving 1 μg/kg single dose of fentanyl and 0.3 mg/kg single dose of ketamine (low‑dose ketamine). Patients’ pain scores and the incidence rate of complications were recorded before the intervention, and 15, 30, and 60 min after drug administration and were then compared between the two groups.

The mean pain score of patients 15 min after the intervention was significantly lower in the low‑dose ketamine group with a mean of 2.50 ± 1.34 as compared with the fentanyl group with a mean of 7.10 ± 1.43 (P < 0.001). However, the mean pain score was not significantly different between the two groups 30 and 60 min after the intervention (P > 0.05). In addition, the incidence rate of complications was not significantly different between the two groups (P > 0.05).

According to the results of this study, low‑dose ketamine as compared with fentanyl relieves pain in the mentioned patients with a faster effect and in a shorter time although no difference can be found between the pain scores of the two groups 30 and 60 min after the intervention.