Evaluation of the Effect of Oral Ketamine Compared to Placebo on Pain Reduction in Patients with Renal Colic: A Double-blind Randomized Clinical Trial Study

Renal colic caused by urolithiasis is among the common causes of severe pain and referral to the emergency rooms. Using a multimodal method in controlling this type of pain with available anesthetics such as ketamine can help relieve pain, increase satisfaction, and reduce hospitalization.

The present study was conducted as a double-blind clinical trial. A total of 44 patients with renal colic with the American Society of Anesthesiologists (ASA) class 1 were divided into intervention and control groups. Pethidine (1mg/kg) was administered to both groups. In the intervention group, oral ketamine (0.5 mg/kg) dissolved in 5% dextrose was prescribed, and in the control group, 5% dextrose serum (0.1 ml/kg) was used. Pain intensity was measured by the numeric rating scale before the treatment and half, one, two, and three hours after the intervention.

The mean age of the intervention group was 35.2, and the control group was 38.9 (P=0.092). The average amount of pethidine consumed in the intervention group was 94 mg, and in the control group was 89 mg, and no significant difference was observed between the two groups (P=0.095). In the intervention group, 27.3% and in the control group, 72.7% needed additional pethidine (P=0.000). In first, second, and third hours after the treatment, the intensity of pain in the intervention group was lower than the control group, and only in the third hour this difference was statistically significant (P=0.03).

In patients with renal colic, adding oral ketamine to intravenous pethidine statistically significantly reduces the consumption of opioid, increases patient satisfaction, and reduces pain intensity three hours after treatment. Therefore, oral administration of ketamine is suggested as an adjunctive drug to relieve the pain of renal colic in hospital emergency.