Pharmacology Of Drospirenone

Indication For the prevention of pregnancy in women who elect an oral contraceptive.
Pharmacodynamics Drospirenone differs from other synthetic progestins in that its pharmacological profile in preclinical studies shows it to be closer to the natural progesterone. As such it has anti-mineralocorticoid properties, counteracts the estrogen-stimulated activity of the renin-angiotensin-aldosterone system, and is not androgenic.
Mechanism of action Progestins such as drospirenone diffuse freely into target cells in the female reproductive tract, mammary gland, hypothalamus, and the pituitary and bind to the progesterone receptor. Once bound to the receptor, progestins slow the frequency of release of gonadotropin releasing hormone (GnRH) from the hypothalamus and blunt the pre-ovulatory LH surge.
Absorption Oral bioavailability is approximately 76%.
Volume of distribution Not Available
Protein binding 97%
Metabolism Extensively metabolized following oral or intravenous administration. The two major metabolites are inactive and are formed independent of the CYP450 enzyme system. The metabolites are the acid form of drospirenone formed by opening of the lactone ring and the 4,5-dihydro-drospirenone-3-sulfate.
Route of elimination Not Available
Half life 30 hours
Clearance Not Available
Toxicity Not Available

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