Can low-dose of ketamine reduce the need for morphine in renal colic? A double-blind randomized clinical trial.

BACKGROUND: The combination of morphine with low doses of ketamine (MK) has been utilized in the Emergency Department (ED) compared with morphine and placebo (MP) for the treatment of acute pain in few studies. The purpose of this study was to compare the effect of MP with MK for the treatment of severe pain with renal colic of patients who had been referred to the ED.

METHODS: This study is a double blind randomized clinical trial on patients with severe renal colic pain who were referred to the ED. Patients were enrolled with pain severity of at least 6 of the 10 visual analogue scales (VAS). Patients were divided into two groups: Morphine 0.1mg/kg and placebo (MP group) and morphine 0.1mg/kg and ketamine 0.15mg/kg (MK group). Pain of patients was studied in 10, 30, 60, 90, and 120min after injection.

RESULTS: Totally, 106 patients were enrolled in study groups. Assessment of the average pain during 120min at 10 and 30min after the start in the drug, MK group was significantly lower than the MP group (p=0.019 and p=0.003 respectively).

CONCLUSION: Given that combinations of morphine with low doses of ketamine in patients with renal colic pain causes more pain and morphine consumption reduction then this combination is suggested as an alternative treatment that could be utilized in patients with renal colic.