Drospirenone

A progestin that behaves a little differently

Drospirenone is a synthetic progestin — one of the medicines that copies the natural hormone progesterone. Its close relative is spironolactone, and it shares two of that drug's habits: it works against aldosterone, the hormone that tells the kidneys to hold on to salt and water, and it damps down androgens (male-type hormones) to some degree. Those extra actions are why it turns up in a combined contraceptive rather than a progestin-only pill.

Here it is paired with ethinyl estradiol, an oestrogen. Together, the two are what people mean by "the combined pill".

What the drospirenone tablet is used for

The drospirenone listing here is Yasmin, tablets of 3mg drospirenone with 0.03mg ethinyl estradiol. It is taken to prevent pregnancy, to treat acne and to ease period symptoms.

Pregnancy is prevented because ovulation is suppressed, and the mucus at the neck of the womb thickens as well. Acne that flares each month is the second reason people choose it: drospirenone blunts androgens, so the skin makes less oil. The third is the bloated, tender week before a period, which eases because the aldosterone block stops the body holding on to as much salt and water. Find it under Women's Health.

Taking it day by day

One tablet a day, at roughly the same time each day — steady levels matter more than the exact hour. Work through the pack in the order printed on the strip, then start the next pack the day after the last tablet so the routine never breaks.

If a tablet comes back up within a few hours, or you have diarrhoea, that dose may not have been absorbed.

Keep the pack in its box, out of direct sun.

Side effects, common and serious

The first two or three packs are often the noisiest. Spotting between periods, tender breasts, headaches, nausea and low mood are the usual complaints, and most ease as the body adjusts.

A blood clot is rare but serious. Painful swelling in a leg, sudden breathlessness or chest pain, a bad headache with visual disturbance, or sudden loss of vision needs urgent treatment.

What interacts with drospirenone

St John's wort, rifampicin and some epilepsy medicines speed up the liver enzymes that clear drospirenone, so the tablet can lose its grip. Drospirenone also nudges potassium levels up, which matters if you take potassium supplements, potassium-sparing diuretics, ACE inhibitors or NSAIDs such as ibuprofen most days. An occasional painkiller is not the concern; it is the daily ones that count.