A double-blind, randomized comparison of intramuscularly and intravenouslyadministered parecoxib sodium versus ketorolac and placebo in a post-oral surgery pain model

Background: Parecoxib sodium is an injectable cyclooxyoenase-2-specific inh ibitor developed for the treatment of acute pain. The analgesic efficacy of IV and IM parecoxib has been demonstrated in previous pilot studies using the post-oral surgery pain model. Objective: This study was conducted to characterize the analgesic efficacy of parecoxib in healthy adults after oral surgery while comparing the effic acy and tolerability of the IV and IM routes of administration. Methods: This was a double-blind, randomized, parallel-group, placebo- and active-controlled, single-dose, single-center trial. Patients experiencing moderate to severe postoperative pain after the extraction of greater than or equal to2 impacted third molars were randomized to receive parecoxib sod ium 20 mg, IM, 20 mg IV, 40 mg IM, or 40 mg IV; ketorolac tromethamine 60 m g IM; or placebo. Patients assessed pain intensity and pain relief (PR) at baseline and at designated intervals for 24 hours after administration of s tudy medication or until rescue medication was taken. Analgesic efficacy wa s assessed in terms of time-specific pain intensity difference (PID) and PR , time to onset of analgesia, and time to use of rescue medication. Results: Three hundred four patients were randomized to treatment. Parecoxi b sodium 20 and 40 mg IM or IV and ketorolac 60 mg EA were significantly su perior to placebo in PID, PR, time to onset of analgesia, and time to use o f rescue medication (P less than or equal to 0.05). Equal IV and IM doses o f parecoxib were comparable on these measures; however, time to use of resc ue medication was longer with IM compared with IV administration. Both dose s of parecoxib were comparable to ketorolac 60 mg IM in time to onset of an algesia, but parecoxib 40 mg had a significantly longer duration of action (P less than or equal to 0.05). The few statistically significant differenc es in PID and PR between parecoxib 40 mg and ketorolac favored ketorolac ve rsus parecoxib 40 mg IV at earlier time points and parecoxib 40 mg IM versu s ketorolac at later time points (P: 0.05). All treatments were well tolera ted. Conclusions: Parecoxib IV and IM provided effective analgesia. The 40-mg do se was comparable to ketorolac 60 mg on most measures of analgesia but had a longer duration of action.