Dexketoprofen

Dexketoprofen is the S(+)-enantiomer of ketoprofen and accounts for ketoprofen's analgesic and anti-inflammatory effects. The inactive R(-)-enantiomer plays no part in these therapeutic effects but does add to the metabolic burden. Dexketoprofen is formulated as a trometamol salt, and its high water solubility allows it to be absorbed rapidly through the gut wall, giving it a faster onset of action than ketoprofen. Peak plasma concentrations are reached more quickly than with other widely used analgesics, with an onset of action of 30 minutes. Given as a tablet, dexketoprofen trometamol is absorbed rapidly, reaching maximum plasma concentration (tmax) within 0.25 to 0.75 hours, compared with a tmax of 0.5 to 3 hours for the S-enantiomer when the racemic drug is given as tablets or capsules made with the free acid. Peak plasma concentrations of 1.4 mg/L and 3.1 mg/L are reached after doses of dexketoprofen trometamol 12.5 mg and 25 mg, respectively. Between 70% and 80% of the administered dose is recovered in the urine within the first 12 hours, mostly as the acyl-glucuronoconjugated parent drug. No R(-)-ketoprofen appears in the urine after dexketoprofen (S(+)-ketoprofen) is given, confirming that the S(+)-enantiomer does not undergo bioinversion in humans. The anti-inflammatory potency of dexketoprofen has consistently matched that of twice the dose of ketoprofen.