Pharmacokinetics of Medroxyprogesterone Acetate Administered by Oral and Intramuscular Route

Abstract

The present study was undertaken to elucidate: 1) The relationship between plasma concentration of medroxyprogesterone-acetate (MPA, ClinovirR, Depo-Provera, Upjohn) administered both orally and intramuscularly. 2) The relation between dose and plasma concentration of MPA.Nineteen patients entered the study. In each patient the plasma concentration was monitored after the administration of a single oral and one intramuscular dose of MPA at the following dosage levels: 100 mg (5 patients), 400 mg (5 patients), 800 mg (5 patients) and 1 200 mg (4 patients). The interval between the oral and i.m. administration was 1 week.The results show: 1) A very large interindividual variation in plasma concentration. 2) An increase in plasma concentration after both oral and i.m. dose. 3) After the i.m. administration, plasma levels remained steady or increased slightly throughout the test period. 4) After the oral administration the concentration increased rapidly to reach a peak by 2-7 hours, subsequently decreasing. Peak concentrations were 2-10 times higher than after i.m. administration. 5 ) Over the test period, the plasma concentration x time (0-168 h) is similar in the two modes of administration.

Medroxyprogesterone acetate binds the glucocorticoid receptor to stimulate α-ENaC and sgk1 expression in renal collecting duct epithelia

“…Our study demonstrates that MPA stimulates the expression of ␣-ENaC transcripts in vivo and ␣-ENaC and sgk1 in CCD cell lines. The peak plasma concentration of MPA following a standard parenteral dose of DepoProvera is 1 to 7 ng/ml (2.5 to 18 nM) (17). The circulating peak concentrations of MPA in vivo are clearly sufficient to increase ␣-ENaC expression in culture (see Fig.…”

The pharmacokinetics of medroxyprogesterone acetate following two different loading dose schedules in advanced carcinoma of the breast

“…For an oral dose of 1,500mg daily it may take from 4 to 20 days to reach plateau levels (Blossey et al, 1984), but interpatient variability is marked (Blossey et al, 1984;Lober et al, 1981), and times of up to 8 weeks have been reported before steady state serum levels have been achieved (Schulz et al, 1984).…”