CLINICAL PHARMACOLOGY
DEPO-PROVERA Contraceptive Injection (medroxyprogesterone
acetate), when administered at the recommended dose to
women every 3 months, inhibits the secretion of gonadotropins
which, in turn, prevents follicular maturation and ovulation
and results in endometrial thinning. These actions produce
its contraceptive effect.
Following a single 150 mg IM dose of DEPO-PROVERA Contraceptive
Injection, medroxyprogesterone acetate concentrations,
measured by an extracted radioimmunoassay procedure, increase
for approximately 3 weeks to reach peak plasma concentrations
of 1 to 7 ng/mL. The levels then decrease exponentially
until they become undetectable (<100 pg/mL) between
120 to 200 days following injection. Using an unextracted
radioimmunoassay procedure for the assay of medroxyprogesterone
acetate in serum, the apparent half-life for medroxyprogesterone
acetate following IM administration of DEPO-PROVERA Contraceptive
Injection is approximately 50 days.
Women with lower body weights conceive sooner than women
with higher body weights after discontinuing DEPO-PROVERA
Contraceptive Injection.
The effect of hepatic and/or renal disease on the pharmacokinetics
of DEPO-PROVERA Contraceptive Injection is unknown.
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