A multicenter, randomized, double-blind, double-dummy, placebo- and active-controlled, parallel-group comparison of diclofenac-K and ibuprofen for the treatment of adults with influenza-like symptoms

Abstract

Background: The alleviation of influenza-like symptoms, such as fever, headache, and muscle/joint aches and pains, is important so that sufferers can return to their normal daily activities. A flexible dosing regimen is proposed, starting with an initial dose of 2 tablets (2 x 12.5 mg), followed by 1 to 2 tablets every 4 to 6 hours as needed, to a maximum daily dose of 75 mg for up to 3 days for fever and 5 days for pain. This flexible dosing regimen matches the existing over-the-counter dosing regimen of ibuprofen, which allows the patient to adjust the treatment according to the type, duration, and severity of symptoms.

Objective: This study assessed the efficacy and tolerability of diclofenac-K 12.5 mg versus ibuprofen 200 mg and placebo against influenza-like symptoms (oral temperature > or = 38.1 degrees C, and at least moderate headache and muscle/joint aches and pains).

Methods: This was a 3-day, multicenter, randomized, double-blind, double-dummy, placebo- and active-controlled, parallel-group trial conducted in Germany. The flexible dosing regimens comprised 2 tablets of diclofenac-K (12.5 mg), ibuprofen (200 mg), or placebo, then 1 to 2 tablets every 4 to 6 hours as needed, to a maximum of 6 tablets/d. Primary efficacy outcomes were fever reduction after the initial dose and an end-of-study global assessment of overall symptom relief. Secondary efficacy outcomes included reduction of feverishness; relief of headache; and relief of muscle/joint aches and pains, after the first dose and at the end of days 1, 2, and 3. Use of rescue medication (paracetamol 500-mg tablets) and usage patterns of study medication were also studied. Tolerability was monitored by recording of patients' adverse events.

Results: A total of 356 patients were enrolled (n = 121, 120, and 115 patients in the diclofenac-K, ibuprofen, and placebo groups, respectively). All patients were white except 1 Asian patient in the diclofenac-K group; 55% to 60% of patients in all 3 groups were male; the mean age in each treatment group was approximately 40 years. At baseline, mean oral temperature ranged from 38.65 degrees C in the placebo group to 38.74 degrees C in the diclofenac-K group. Mean oral temperatures in both active groups were significantly lower than that of the placebo group from 30 minutes through 6 hours (P < 0.001), dropping 0.85 degrees C after 4 hours in the diclofenac-K group and 0.76 degrees C in the ibuprofen group versus 0.32 degrees C for placebo. In the end-of-study global treatment assessment, 89.0% of diclofenac-K and 89.1% of ibuprofen patients rated global efficacy as "good" to "excellent" versus only 32.1% for placebo. Diclofenac-K was superior to placebo (P < 0.001) and similar to ibuprofen on all direct assessments of fever and aches and pains. Both active treatments were as well tolerated as was placebo.

Conclusions: In this 3-day study, diclofenac-K 12.5 mg taken in a flexible dosing regimen was more effective than placebo in relieving influenza-like symptoms, with comparable tolerability Efficacy and tolerability of diclofenac-K were similar to those of ibuprofen 200 mg.