The pharmacokinetic profile of naproxen suppository in man.

After a rectal dose of 500 mg in a suppository, naproxen is 6-O-demethylated (20%) and glucuronidated (40%), the metabolites are subsequently excreted renally. The elimination half-life is 15.2 +/- 2.6 h. Ten out of 22 subjects show biphasic elimination kinetics with half-lives of 7 and 15 h, respectively. There is a wide range in the percentage of the dose that is glucuronidated and demethylated (20-70%). This variation does not deviate from a normal distribution.