Onset of action of diclofenac potassium liquid-filled capsules in dental surgery patients

Objective: Diclofenac potassium soft gelatin capsules (DPSGC) are a low-dose, liquid-filled formulation that uses patented dispersion technology to facilitate rapid and consistent gastrointestinal absorption. Onset of pain relief experienced by patients receiving DPSGC was evaluated in two dental pain studies. Confirmed perceptible pain relief was evaluated in a post hoc analysis from these randomized controlled trials. Research design and methods: Adult patients (n=514) were enrolled in two multicenter, parallel group, double-blind, placebo-controlled studies. Patients undergoing third molar extraction and experiencing a requisite level of pain (≥50mm on a 100-mm visual analog scale within 4 hours post-surgery) were randomized to receive single doses of DPSGC 25mg, 50mg, 100mg, or placebo. Pain was assessed at baseline and during 6 hours after dosing. Times to onset of perceptible and meaningful pain relief were recorded using the two-stopwatch method. Confirmed perceptible pain relief was determined in the DPSGC and placebo groups by calculating the median time to onset of perceptible pain relief (first stopwatch) in only those individuals who reported meaningful pain relief (second stopwatch). Results: More than 80% of patients achieved confirmed perceptible pain relief in the DPSGC groups compared with less than 30% of patients in the placebo group (Study 1 and Study 2, p<0.0001). The median time to onset of confirmed perceptible pain relief in the two studies was less than 30 minutes for patients receiving any dose of DPSGC and more than 360 minutes in the placebo group (Study 1 and Study 2, p<0.0001). DPSGC was well tolerated and no serious adverse events were reported. Study design limitations include the short duration of the trial and evaluation of a relatively limited patient population. Conclusions: These results indicate that DPSGC was efficacious in providing a rapid onset of confirmed perceptible pain relief within 30 minutes of administration in these single dose postoperative dental pain studies.