Relief of Acute Low Back Pain with Diclofenac-K 12.5 Mg Tablets: a Flexible Dose, Ibuprofen 200 Mg and Placebo-controlled Clinical Trial

Objective: To assess efficacy and safety of diclofenac-K 12.5 mg tablets in the treatment of acute low back pain (low back pain).

Material/method: A multiple dose, double-blind, double-dummy, randomized, placebo-controlled, parallel group trial compared diclofenac-K (12.5 mg; n = 124) with ibuprofen (200 mg; n = 122) and placebo (n = 126) in patients with moderate-to-severe acute low back pain. The treatment consisted of an initial dose of 2 tablets followed by 1 or 2 tablets every 4-6 hours as needed (maximum 6 tablets/day) for 7 days. The primary efficacy outcome for the initial dose was TOTPAR-3, the summed total pain relief over the first 3 hours. Secondary initial dose outcomes included TOTPAR-6, summed pain intensity differences SPID-3 and SPID-6, time to rescue medication or remedicate, and the End of First Dose global efficacy assessment. The primary efficacy outcome for the flexible multiple dosing regimen was the End of Study global efficacy assessment. Secondary outcomes for multiple dosing included time to rescue medication over the entire study, the End of Day global efficacy assessments (daily over Days 1-7), pain intensity differences on the VAS measured at Visit 2 and 3, and change in Eifel algofunctional index. Safety/tolerability was assessed by recording adverse events.

Results: Diclofenac-K 12.5 mg demonstrated superiority vs placebo on the primary efficacy parameter and almost all secondary initial dose outcomes. With respect to the initial dose, diclofenac-K 12.5 mg was also significantly superior to ibuprofen 200 mg on SPID-3. Ibuprofen 200 mg was superior to placebo only on the End of First Dose global efficacy assessment. The flexible multiple dosing regimens of diclofenac-K and ibuprofen were both significantly superior to placebo on the End of Study global efficacy assessment, time to rescue medication over the entire study period, the End of Day global efficacy assessment on Days 1-2, pain intensity difference on the VAS at Visit 3 and the Eifel algofunctional index at Visit 3 (also at Visit 2 in diclofenac-K 12.5 mg group). Both active treatments were as well tolerated as placebo.

Conclusions: The flexible multiple dosing regimen of diclofenac-K 12.5 mg (initial dose of 2 tablets followed by 1-2 tablets every 4-6 hours, max. 75 mg/day) is an effective and safe treatment of acute low back pain.