Analgesic safety and efficacy of diclofenac sodium softgels on postoperative third molar extraction pain

Abstract

Purpose: The purpose of this single-blind, placebo-controlled, 3-arm parallel, randomized study was to compare the analgesic efficacy and tolerability of a single dose of 100 mg diclofenac potassium (Cataflam; Novartis, Stein, Switzerland), 100 mg diclofenac sodium softgel, and placebo in patients experiencing moderate to severe postoperative pain after third molar extraction.

Patients and methods: Seventy-five patients (67% female with a mean age of 23, age range 18 to 34.5 years) participated in the study following removal of at least 1 impacted mandibular third molar. Patients received a single dose of study medication when their postoperative pain reached a moderate or severe intensity. Analgesic efficacy measures included the time to meaningful pain relief measured using a stopwatch and time to rescue medication. Pain relief (PR) and Pain intensity (PI) ratings were recorded at 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 5, 6, 8, and 24 hours postdosing. Summary analgesic measures, including Summed Pain Relief Score (TOTPAR) and Summed Pain Intensity Differences (SPID), were calculated from the 0.25- to 6-hour responses. The time between pain relief and rescue and a global evaluation for the effectiveness of the study medications were recorded at the end of the study. Seven scheduled blood samples were collected from each patient for determining plasma concentrations of diclofenac anion.

Results: Both diclofenac sodium softgel and Cataflam were significantly more effective than placebo (P <.0001) for all summary analgesic measures. The average overall pain relief was substantially better from diclofenac sodium softgel than from Cataflam, but the difference was not statistically significant (P =.14). In patients taking diclofenac sodium softgel, 50% of the patients experienced a time to onset of analgesic activity within 18 minutes and the median analgesic duration was 5 hours (302 minutes). Fifty percent of the patients taking Cataflam had a time to onset of action within 38 minutes, and the median duration of analgesia was 4.5 hours (272 minutes). At the time of rescue drug administration or 6 hours, whichever was earlier, 72% of the patients given diclofenac sodium softgel rated the medication as a very good or excellent pain reliever, whereas only 45% of the patients taking Cataflam gave these ratings. No serious adverse events were observed in this study. The mean concentrations of diclofenac from the diclofenac sodium softgel formulation were significantly different from the Cataflam formulation. The mean C(max) for the softgel was almost twice that of Cataflam and C(max) was reached an hour earlier, on average.

Conclusions: More diclofenac anion was absorbed at a quicker rate using the formulation diclofenac sodium softgel 100 mg than Cataflam. The softgel provided a very rapid onset of analgesic activity, a prolonged analgesic duration, and an acceptable side-effect profile in the postoperative third molar surgery pain model. In an acute pain situation, the rapid absorption of nonsteroidal anti-inflammatory drugs from a formulation like the Softgel may positively affect the time of onset and duration of inflammatory pain compared with other commercially available nonsteroidal anti-inflammatory drug formulations.