Intrathecal nalbuphine at two doses reduces opioid use and pain after total knee arthroplasty: a randomized controlled trial.

PURPOSE

This study aimed to assess the efficacy of different-dose intrathecal nalbuphine (ITN) in addition to adductor canal block (ACB) and its associated side effects.

METHODS

This prospective randomized double-blinded controlled trial recruited 42 patients undergoing TKA at Naresuan University Hospital who received spinal anesthesia and ACB into three groups, each with 14 patients: Group A (control), Group B (additional ITN 0.8 mg), and Group C (additional ITN 1.2 mg). The primary outcome was the numeric rating scale (NRS) at rest and during movement at various time points. The secondary outcomes included the cumulative morphine use (CMU) and side effects.

RESULTS

Forty-two patients (group A = 14; group B = 14; group C = 14) were randomized. All patients were analyzed. The group C had significantly lower NRS at rest at 6, 12, 24, and 48 h postoperatively, and significantly lower NRS during movement at 6 and 36 h postoperatively when compared to group A. There was no significant difference in NRS between group C and B, or between group B and A. The group B and C required significantly less CMU than the group A during the first 24, 48, and 72 h after TKA. The side effects, which included nausea, vomiting, drowsiness, respiratory depression, and shivering, were not significantly different among the groups.

CONCLUSION

Additional ITN, both 0.8 and 1.2 mg doses, effectively reduces CMU during the first 72 h after TKA. Given higher-dose ITN up to 1.2 mg provides benefit by further reducing pain scores, without increased side effects.

TRIAL REGISTRATION CLINICAL TRIALS

TCTR20241012005, October 12, 2024.