[Analgesic efficacy and the tolerance for piroxicam-beta-cyclodextrin compared to piroxicam, paracetamol and placebo in the treatment of postextraction dental pain].

INTRODUCTION: Acute postoperative pain is a common experience in oral surgery practice. Non-steroidal anti-inflammatory drugs (NSAIDs) are quite effective against mild to moderate pain and they are generally better suited in ambulatory outpatients than narcotic analgesics. The analgesic activity of piroxicam, a well known NSAID has been documented in many pain states. Piroxicam can be administered once daily because of its long half-life, but its absorption in the gastrointestinal tract is slow as it is its onset of action. Piroxicam-beta-cyclodextrin (PBCD) is a new formulation of piroxicam which is the product of supermolecular encapsulation of piroxicam with the cyclic oligosaccharide beta-cyclodextrin. PBCD is absorbed much faster than standard piroxicam, and its action as an analgesic is consequently more rapid. The purpose of this study was to assess the efficacy and the rapidity of action of piroxicam-beta-cyclodextrin in comparison with standard piroxicam, paracetamol and placebo following surgical extraction of impacted third molars.

MATERIALS AND METHODS: The study population was composed of 32 patients of both sexes and in good health. To be included into the study, patients must have had third molar removal resulting in acute post-surgical pain of at least moderate intensity. The patients were then randomly assigned to one of four treatment groups. PBCD 20 mg tablets; piroxicam 20 mg capsules; paracetamol 500 mg tablets, or placebo. The study was conducted according to a double-blind, double-dummy design. Pain intensity and pain relief were recorded at 0.5, 1, 1.5, 2, 3, 4 hours after a single dose of the study drugs, by means of a Keele-type rating scale. Rescue analgesics were not allowed before one and a half hour after taking the study drugs. A global evaluation of study drugs was expressed by patients at the end of the observation period.

RESULTS: Treatment groups were homogeneous for demographic characteristics of the patients and for pain intensity at the time of medication with study drugs. All patients who received placebo requested supplemental analgesics, while none of the patients treated with the active drugs needed rescue analgesics. PBCD and paracetamol were comparable for their analgesic effect, while the time lag before a significant reduction of pain intensity with piroxicam was longer. Piroxicam and PBCD were superior to paracetamol because they showed a substantial analgesic effect through the 4-hour study duration, while paracetamol did not induce a complete relief from pain.

DISCUSSION: One of the most commonly utilized model for the evaluation of analgesics is the third molar extraction pain. Our study clearly differentiated between active drugs and placebo. Furthermore, while PBCD and paracetamol showed a rapid effect, piroxicam was slow in inducing pain relief. The analgesic and anti-inflammatory activity of PBCD and piroxicam brought about the resolution of pain and inflammation consequent to the dental extraction. Paracetamol, a pure analgesic, was not equally active and pain persisted, even if at a low grade, throughout the observation period; probably this was due to local inflammation and edema. The results of our study appear to confirm the pharmacokinetic data on PBCD, which showed that therapeutic blood levels are reached faster with PBCD than with the standard piroxicam formulation. This results should be confirmed in studies with an adequate number of patients.