An assessment of the efficacy and safety of diclofenac potassium liquid-filled capsules in patients with various levels of baseline pain intensity

Abstract

Context:

Diclofenac potassium liquid-filled soft gelatin capsule (DPSGC; Zipsor^*) is a novel formulation of diclofenac potassium used to treat mild to moderate acute pain.

Objective:

To investigate whether DPSGC 25 mg provided significant reduction in pain intensity compared with placebo, regardless of baseline pain intensity, a post hoc analysis was performed of pooled data from two replicate randomized controlled trials (NCT00366444 and NCT00375934) that evaluated the safety and efficacy of DPSGC in postbunionectomy treatment.

Methods:

Patients from the two randomized trials were assigned to one of two subgroups: patients with baseline numerical pain rating scale (NPRS) scores of 4 or greater to less than 7 and those with baseline NPRS scores of 7 or greater. Within each subgroup, efficacy and safety of DPSGC was compared with placebo.

Results:

Across the two studies, 73 DPSGC- and 59 placebo-treated patients had baseline pain intensity scores ranging from 4 or greater to less than 7, while 128 DPSGC- and 141 placebo-treated patients had baseline pain intensity scores of 7 or greater. Significantly lower mean 48-hour NPRS scores were observed in the DPSGC group, regardless of baseline pain intensity (P < 0.0001). In both subgroups, at least twice as many patients treated with DPSGC rated the study drug as very good or excellent compared with patients taking placebo. Potential limitations for this post hoc analysis include study design and patient population. As with all studies investigating treatment for pain, the use of rescue medication may also be a potential limitation.

Conclusions:

DPSGC provided significantly greater improvements in pain compared with placebo following bunionectomy, regardless of patients’ baseline pain level.

Key words::

• Diclofenac
• Nonsteroidal anti-inflammatory drugs
• Pain intensity

Transparency

Declaration of funding

This study was funded by Xanodyne Pharmaceuticals Inc., Newport, KY, USA.

Declaration of financial/other relationships

S.E.D. has disclosed that he is an employee of Premier Research Group Ltd, which was paid to perform one of these studies. D.R., E.D., and F.C. have disclosed that they were reimbursed for their participation as principal investigators in the study. D.R. and F.C. have no other financial relationships to disclose. E.D. disclosed that he is a paid speaker for Xanodyne Pharmaceuticals Inc. S.E.B. is a full-time employee of Xanodyne Pharmaceuticals Inc.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.

Acknowledgment

The authors would like to thank Lamara D. Shrode, PhD, ISMPP Certified Medical Publication Professional, of The JB Ashtin Group Inc., for assistance in preparing this manuscript for publication based on the authors’ input and direction. The authors take full responsibility for all content. The authors verify that they have met all of the journal’s requirements for authorship. The authors received no compensation for this work.

Notes

* Zipsor is a registered trademark of Xanodyne Pharmaceuticals Inc., Newport, KY, USA.

* Zipsor is a registered trademark of Xanodyne Pharmaceuticals Inc., Newport, KY, USA.

† ProSorb is a registered trademark of Xanodyne Pharmaceuticals Inc., Newport, KY, USA, licensed from AAIPharma Services Inc., Wilmington, NC, USA.