Efficacy and tolerability of a new powdered formulation of diclofenac potassium for oral solution for the acute treatment of migraine: Results from the International Migraine Pain Assessment Clinical Trial (IMPACT)

Richard B. Lipton, Brian Grosberg, Richard P. Singer, Starr H. Pearlman, James V. Sorrentino, John N. Quiring, Joel R. Saper

Research output: Contribution to journalArticle

38 Scopus citations


Objective: This study assessed the efficacy of diclofenac potassium for oral solution, a novel water-soluble buffered powder formulation, versus placebo for the acute treatment of migraine. Diclofenac potassium for oral solution has a time to maximum plasma concentration (Tmax) of 15 minutes, suggesting the potential for a rapid onset of therapeutic effects. Methods: This was a randomized, double-blind, parallel-group, placebo-controlled study conducted in 23 US centers. Adult sufferers with an established migraine diagnosis according to the International Classification of Headache Disorders, second edition (ICHD-II), treated one moderate or severe attack with 50 mg diclofenac potassium for oral solution (dissolved in approximately 2 ounces of water; N = 343) or matching placebo (N = 347). Four co-primary endpoints included the percentage of subjects who at two hours post-treatment reported no headache pain, no nausea, no photophobia and/or no phonophobia. Results: Significantly more subjects treated with diclofenac potassium for oral solution (N = 343) achieved a two-hour pain-free response (25% vs. 10%, p <.001), no nausea (65% vs. 53%; p =.002), no photophobia (41% vs. 27%; p <.001) and no phonophobia (44% vs. 27%; p <.001) compared to placebo. Pain intensity differences between treatments were significantly lower in the diclofenac potassium oral solution group, starting at 30 minutes post-treatment (p =.013) with significant differences at all time points thereafter (p <.001). Twenty-four-hour sustained pain-free response favored diclofenac potassium oral solution treatment versus placebo (19% vs. 7%, p <.0001). The most common adverse event considered to be treatment related was nausea (diclofenac potassium for oral solution [4.6%]; placebo [4.3%]). Conclusions: This study shows that this formulation of diclofenac potassium for oral solution is effective in reducing pain intensity within 30 minutes, which may be related to the 15-minute Tmax associated with this formulation. The rapid-onset benefits were sustained through 24 hours post-treatment.

Original languageEnglish (US)
Pages (from-to)1336-1345
Number of pages10
Issue number11
StatePublished - Nov 1 2010



  • acute treatment
  • buffered formulation
  • diclofenac potassium
  • migraine

ASJC Scopus subject areas

  • Clinical Neurology

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