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).
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 T(max) associated with this formulation. The rapid-onset benefits were sustained through 24 hours post-treatment.
Lipton
Richard B
RB
Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA. rlipton@aecom.yu.edu
Grosberg
Brian
B
Singer
Richard P
RP
Pearlman
Starr H
SH
Sorrentino
James V
JV
Quiring
John N
JN
Saper
Joel R
JR
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000009:adverse effects; D004008:Diclofenac / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000188:drug therapy*; D011208:Powders; D016896:Treatment Outcome; D055815:Young Adult
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011208:Powders; D004008:Diclofenac