Superior efficacy of intramuscular diclofenac compared to intravenous tramadol for acute renal colic in northern Thai patients: A randomised double-blind, sham-controlled trial.

OBJECTIVE

The present study aimed to compare time to effective pain relief between diclofenac 75 mg intramuscular (IM) and tramadol 50 mg intravenous (IV) for ED patients with acute renal colic.

METHODS

A randomised, double-blinded, sham-controlled, superiority trial was conducted. Patients diagnosed with acute renal colic (hydronephrosis and/or stone visualisation on point-of-care ultrasound) in the ED were randomly assigned to receive an IM injection of 75 mg of diclofenac or IV tramadol 50 mg. Pain relief was defined as a numerical rating scale reduction of two or more points (standard 0-10 scale) and a reduction of at least one level of pain transition question ('much better', 'little better', 'unchanged', 'little worse', 'much worse'). The primary outcome was the multivariable-adjusted subdistribution-hazard ratio (SHRs) within 120 min in the ED, estimated using the cumulative incidence function (CIF). The secondary outcome compared the average time to pain relief using the restricted mean survival time (RMST).

RESULTS

A total of 68 patients were randomised, with 34 patients allocated to each group. At the 120 min, pain relief was reported in diclofenac and tramadol, 32 (94%) and 22 (65%) patients respectively. SHR was 2.86 (95% CI: 1.80-4.55; P value <0.001). For diclofenac and tramadol, the RMSTs were 37.09 min (95% CI: 30.00, 44.15) and 78.74 min (95% CI: 66.49, 90.99) respectively, with the difference of 41.67 min (95% CI: 55.71, 27.62).

CONCLUSION

Diclofenac 75 mg IM provides faster effective pain relief compared with tramadol 50 mg IV.