Lowest Effective Single Dose of Diclofenac for Antipyretic and Analgesic Effects in Acute Febrile Sore Throat

Abstract

To compare the antipyretic and analgesic effects of a single oral dose of diclofenac potassium 6.25, 12.5 or 25mg with paracetamol 1000mg and placebo in patients with fever resulting from acute febrile sore throat. This was a multicentre, double-blind, double-dummy, randomised, placebo-controlled, parallel group study conducted at 21 primary-care centres throughout France. In total, 343 adult patients with acute febrile sore throat (fever >/=38.0 degrees C) were randomised to the five treatment groups. Patients received one oral dose of medication. Fever, spontaneous throat pain and pain on swallowing were recorded over 6 hours. If acute symptoms persisted 2 hours after study drug administration, the patient was allowed to take rescue medication and discontinue the trial. The antipyretic effects of diclofenac potassium 6.25, 12.5 and 25mg and paracetamol 1000mg were significantly greater than placebo. The antipyretic effects of diclofenac potassium 12.5 and 25mg were numerically greater than paracetamol 1000mg, which was comparable to the effect of diclofenac potassium 6.25mg. The analgesic effects of the higher doses, diclofenac potassium 12.5 and 25mg, and of paracetamol 1000mg were significantly better than placebo. Summary efficacy measures over the first 4 hours post-dose showed a dose-response relationship among the diclofenac doses, with statistically significant differences on some outcomes between the 25mg and the 6.25mg doses. On the global efficacy evaluation for relief of fever and throat pain, patients rated both diclofenac potassium 12.5 and 25mg significantly higher than paracetamol 1000mg (p </= 0.01). In contrast, paracetamol 1000mg and diclofenac 6.25mg were not rated significantly higher than placebo. Diclofenac potassium was well tolerated, with a safety profile comparable to that of placebo, and slightly favourable compared with that of paracetamol. Diclofenac potassium administered as single doses of 12.5 and 25mg significantly reduced fever and throat pain in patients with acute febrile sore throat. The overall efficacy of these doses was rated significantly higher than that of paracetamol 1000mg or placebo. A dose-response relationship was seen between placebo and the three diclofenac doses. On most outcomes, paracetamol 1000mg was similar to or only slightly better than the diclofenac potassium 6.25mg dose. Diclofenac potassium 12.5mg is the lowest unit dose that could be recommended to provide reliable reduction of oral temperature and relief of throat pain.