Drospirenone

Medical uses

Drospirenone is an ingredient in some birth control pills and hormone replacement therapy. In combination with ethinylestradiol it is used as contraception, and for women who want contraception it is also approved by the U.S. Food and Drug Administration (FDA) to treat moderate acne and premenstrual dysphoric disorder.

Adverse effects

Drospirenone is an aldosterone antagonist with potassium-sparing properties, though in most cases no increase of potassium levels is to be expected. In women with mild or moderate renal insufficiency, or in combination with chronic daily use of other potassium-sparing medications (ACE inhibitors, angiotensin II receptor antagonists, potassium-sparing diuretics, heparin, aldosterone antagonists, or NSAIDs), a potassium level should be checked after two weeks of use to test for hyperkalemia. In addition to contraindications common to all combined estrogen-progestin medications, drospirenone-containing medications are contraindicated in women with severe renal insufficiency according to European Medicines Agency (EMA)-approved labels, and contraindicated in women with renal insufficiency, adrenal insufficiency, or liver disease according to FDA-approved labels.

Women who take contraceptive pills containing drospirenone have a six- to sevenfold risk of developing thromboembolism (dangerous blood clots) compared to women who do not take any contraceptive pill, and have twice the risk (some epidemiological studies suggest thrice, according to the FDA) compared to women who take a contraceptive pill containing levonorgestrel, though the actual risk is small, in the neighborhood of 9 to 27 out of 10,000 women on an oral contraceptive for a year (up to 9 for levonorgestrel vs up to 27 for drospirenone, or about 0.09% vs 0.3% per year.)

While all oral contraceptives can increase the risk for venous thrombembolic events, including fatal blood clots, several studies have reported a greater risk for women taking contraceptives containing drospirenone. (Before becoming alarmed at the huge "relative" differences in risk, one must remember that the "actual" risks involved are quite small — in the neighborhood of 1 in 10,000 to 27 in 10,000 in a year).

When the U.S. Food and Drug Administration (FDA) became concerned about the risks of drospirenone, they funded studies based on the medical records of more than 800,000 women taking oral contraceptives. They found that the risk of VTE, which includes dangerous and potentially fatal blood clots, was 93% higher for women who had been taking oral contraceptives made with drospirenone for only 3 months or less and 290% higher for women taking drospirenone oral contraceptives for 7–12 months, compared to women taking other types of oral contraceptives. To determine the exact risk for women of different ages and different circumstances, further study is warranted.

The FDA recently updated the label for contraceptives containing drospirenone to include warnings for stopping use prior to and after surgery, and to warn that contraceptives with drospirenone may have a higher risk of dangerous blood clots.

Pharmacodynamics

Drospirenone binds strongly to the progesterone receptor (PR) and mineralocorticoid receptor (MR), with lower affinity, to the androgen receptor (AR), and very low affinity for the glucocorticoid receptor (GR). It is an agonist of the PR and an antagonist of the MR and AR, and hence, a progestogen, antimineralocorticoid, and antiandrogen. Drospirenone is said to be devoid of any estrogenic or glucocorticoid or antiglucocorticoid activity. It has potent antigonadotropic effects at sufficient dosages as a result of PR activation. It has been regarded that drospirenone has a pharmacological profile that is very closely related to that of natural progesterone, due to the combination of both progestogenic and antimineralocorticoid actions.

Drospirenone is 8–10 times more potent as an antimineralocorticoid relative to spironolactone (3 mg drospirenone is equivalent to about 20–25 mg spironolactone in this regard). It is more potent as an antiandrogen relative to spironolactone also but is less potent relative to cyproterone acetate, having about one-third the potency of this drug. Progestogenic, antimineralocorticoid, and mild antiandrogenic effects have been observed in humans during treatment with drospirenone at a dosage range of 0.5 to 4 mg per day orally.

The antimineralocorticoid properties exhibited by drospirenone promote sodium excretion and prevent water retention.

Pharmacokinetics

Drospirenone is taken orally with about 76% bioavailability. It is bound not by sex hormone-binding globulin or corticosteroid binding globulin, but by other serum proteins. Metabolites have not been shown to be biologically active, show up in urine and feces, and are essentially completely excreted within 10 days.

Chemistry

It is an analog to spironolactone, with a molecular weight of 366.5 and the molecular formula C₂₄H₃₀O₃.

Formulations

The compound is part of certain newer oral contraceptive formulations:

Litigation

In January 2011 the CBC TV program Marketplace ran a segment discussing issues involved with the usage of Yaz/Yasmin.

In July 2012, Bayer notified its stockholders that there were more than 12,000 lawsuits against the company involving Yaz, Yasmin, and other oral contraceptives with drospirenone, and that the company by then settled 1,977 cases for $402.6 million, for an average of $212,000 per case, while setting aside $610.5 million to settle the others.