Drospirenone

How drospirenone works

Drospirenone is a synthetic progestin derived from spironolactone. It binds to three receptors and produces three distinct effects there. On the progesterone receptor, it acts as an agonist and reproduces the action of the natural hormone. On the mineralocorticoid receptor, it acts as an antagonist, which gives it anti-aldosterone activity. On the androgen receptor, it also acts as an antagonist, hence an anti-androgen effect.

On the anti-mineralocorticoid side, about 3 to 4 mg of drospirenone are roughly equivalent to 20 to 25 mg of spironolactone. In contraceptive practice, the desired effect comes from suppressing ovulation, which drospirenone ensures either combined with an estrogen or on its own in the progestin-only pill. The two other sides, anti-aldosterone and anti-androgen, explain much of its secondary uses and of the effects to watch. It is this triple profile that sets the molecule apart from other progestins.

Why it is prescribed

Drospirenone is most often part of combined pills, paired with ethinylestradiol. Common doses are 30 µg of ethinylestradiol with 3 mg of drospirenone (Yasmin) and 20 µg with 3 mg (Yaz). Its first indication is contraception, where it reliably blocks ovulation. Thanks to its anti-androgen profile, it is also used in moderate acne, premenstrual syndrome and premenstrual dysphoric disorder.

It also exists as a progestin-only pill, without estrogen, which broadens its use to women for whom estrogens are not advised. The choice between a combined pill and a progestin-only pill depends on each woman's situation and is decided with the doctor. In every case, the logic stays the same: prevent ovulation while making the most of the molecule's own effects. The secondary hormonal indications, acne or premenstrual syndrome, follow directly from its anti-androgen action.

How to take it day to day

Drospirenone is taken by mouth, one tablet once a day. Absorption does not depend on meals: the tablet is taken with or without food, at whatever time fits the day best. Its oral bioavailability is between 66 and 85 %, and the blood concentration reaches its peak 1 to 6 hours after intake. Its elimination half-life is around 30 hours, with a reported range of 25 to 33 hours.

Regularity is what makes a pill effective. Taking the tablet at a set time keeps coverage stable and limits missed doses. Stopping on your own, in the middle of a pack, exposes you to a risk of pregnancy and can disturb the cycle. Any break, any change of pill is discussed with the professional who oversees the contraception, never alone.

The effects to know about

Drospirenone's most specific effect stems from its anti-aldosterone activity: it tends to retain potassium. Persistent hyperkalemia requiring treatment to be stopped occurred in about 2 women out of 1000, that is 0.2 %, on 4 mg per day of drospirenone alone in clinical trials. This event remains rare, but it explains the particular vigilance in women already exposed to excess potassium. In most users whose kidneys work normally, potassium balance stays under control.

On the drospirenone-only progestin pill, the reported side effects include acne flare-ups, follicular ovarian cysts and menstrual irregularities. These irregularities, intermenstrual bleeding or shifted cycles, are common at the start of use and often ease over time. Follicular ovarian cysts are most often benign and regress spontaneously. Acne flare-ups can be surprising, as the molecule is otherwise used against acne in its combined forms.

On the plate

Combined oral contraceptives, those that contain an estrogen, have been associated with a decline in folate status. This is why some drospirenone combinations, such as Beyaz and Safyral, add levomefolate directly. On the plate, folate comes mainly from leafy green vegetables such as spinach, legumes such as lentils and chickpeas, broccoli and oranges. These same foods also cover part of the need for B-group vitamins.

Potassium deserves special attention with this molecule. Since drospirenone tends to retain it, women at risk of hyperkalemia do not need to load up on foods rich in it, and this balance is settled with the doctor. In others, the potassium in bananas, avocados, potatoes and yogurt keeps its full place in a varied diet. On top of your treatment, never in its place, a targeted intake of folate makes sense when diet alone does not offset what the pill shifts.

This targeted intake makes sense in light of an observed association: combined contraceptives containing an estrogen have been associated with a decline in folate status, which diet alone does not always make up for. A supplement that targets folate and B vitamins precisely then meets the same ground as the treatment, without ever replacing it.

Interactions and monitoring

Drospirenone is oxidized by CYP3A4, in addition to pathways independent of CYP450. Strong CYP3A4 inducers speed up its elimination and can reduce its contraceptive effectiveness. Conversely, under a strong CYP3A4 inhibitor taken over a prolonged period, monitoring of potassium is advised during the first month. This enzyme interplay is why any other medication should be reported to the prescriber.

The second axis of monitoring concerns potassium. A measurement of blood potassium is recommended in women at risk: renal, hepatic or adrenal insufficiency, or the use of medications that raise potassium. These medications include non-steroidal anti-inflammatory drugs, potassium-sparing diuretics, potassium supplements, angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists, heparin and aldosterone antagonists. This monitoring targets the situations where potassium could rise beyond what is desirable.