Does co-treatment with ultra-low-dose naloxone and morphine provide better analgesia in renal colic patients?

Abstract

Objective: This study attempted to evaluate the efficacy of ultra-low-dose intravenous (IV) naloxone combined with IV morphine, as compared to IV morphine alone, in terms of reducing pain and morphine-induced side effects in patients with renal colic.

Methods: In this double-blind clinical trial, 150 patients aged 34 to 60 years old who presented to the emergency department (ED) with renal colic were randomly allocated to either an intervention group that received ultra-low-dose IV naloxone combined with IV morphine or to a control group that received morphine plus a placebo. The severity of pain, sedation, and nausea were assessed and recorded for all patients at entrance to the ED (T1), then at 20 (T2), 40 (T3), 60 (T4), 120 (T5), and 180 (T6) minutes after starting treatment. The Numeric Rating Scale (NRS) was used for the assessment of pain and nausea intensities, and the Ramsay Sedation Scale (RSS) was used to assess sedation.

Results: A GEE model revealed that patients in the naloxone group had non-significantly reduced pain scores compared to those in the morphine group (coefficient = -0.68; 95% CI: -1.24 to -0.11, Wald X2 (1) = 5.41, p = 0.02). The sedation outcome demonstrated no statistically significant differences at T1 to T4 among patients with renal colic compared to the ones who only received morphine. At T5 and T6, 1.5% vs. 20% and 1.5% vs. 16.9% of subjects from the naloxone group versus the morphine group obtained RSS scores equal to 3, respectively (p = 0.001 and p = 0.004, respectively).

Conclusions: Compared to patients who only received IV morphine, co-treatment of ultra-low-dose naloxone with morphine could not provide better analgesia and sedation/agitation states in renal colic patients.

Keywords: Analgesia; Emergency department; Morphine; Naloxone; Numeric Rating Scale (NRS); Ramsay Sedation Scale (RSS); Renal colic.