Diclofenac epolamine is effective in the treatment of acute migraine attacks. A randomized, crossover, double blind, placebo-controlled, clinical study. 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).
Hydrosoluble diclofenac epolamine (DHEP) represents an interesting approach to acute migraine attacks, where gastrointestinal motility and drug absorption are often reduced. Its efficacy was investigated in a randomized, crossover, double-blind trial on 155 patients who treated four consecutive mild-to-moderate migraine attacks, either with DHEP (65-mg sachet) or placebo. If pain was not relieved within 1 h, a second dose was given. The total number of treated attacks was 481. A pain-free condition was achieved within 2 h in 45.8% and 25.1% of attacks treated, respectively, with DHEP or placebo (P < 0.0001), with a therapeutic gain of 20.7%. Time to attack resolution, light and noise sensitivity and impact on working ability were significantly reduced by DHEP compared with placebo. Moreover, significantly fewer patients required a second drug dose or a rescue medication when treated with DHEP than with placebo. No adverse reaction was recorded. In conclusion, DHEP was effective and safe for pain relief in patients with an acute mild-to-moderate migraine attack. 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.
                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.
                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%]).
                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 T(max) associated with this formulation. The rapid-onset benefits were sustained through 24 hours post-treatment.
Oral diclofenac potassium 50 mg is an effective treatment for acute migraine, providing relief from pain and associated symptoms, although only a minority of patients experience pain-free responses. Adverse events are mostly mild and transient and occur at the same rate as with placebo.