Drospirenone Pill

Drospirenone progestin-only pills contain drospirenone 4 mg in each of 24 active tablets, followed by 4 inactive tablets in a 28-day pack. Drospirenone is a progestin with anti-mineralocorticoid and anti-androgenic activity. It suppresses ovulation consistently, giving a late-tablet window of 24 hours.

Mechanism. Ovulation suppression, thickened cervical mucus and endometrial thinning.

Pharmacokinetics. Elimination half-life is about 30 hours. Drospirenone opposes aldosterone and can raise serum potassium.

Effectiveness. Pill class estimates apply: typical use 9 and perfect use 0.3 pregnancies in 100 women in the first year. Product-specific typical-use data are limited.

Return to fertility. Rapid after stopping.

Ideal candidates. Patients needing an oestrogen-free pill with a 24-hour timing margin who have normal renal and adrenal function.

Assessment. Medicine history (potassium-raising drugs), renal and liver history, blood pressure, and breastfeeding status. Measure serum potassium in the first cycle in patients with mild or moderate renal impairment or on potassium-raising medicines. Pelvic examination is not needed. Exclude pregnancy by the usual criteria, with a test if none applies.

Contraindications.

• Severe renal impairment or acute renal failure.
• Adrenal insufficiency.
• Severe liver disease, or liver tumour.
• Current breast cancer (category 4); past breast cancer (category 3).
• Unexplained abnormal vaginal bleeding: evaluate before starting.
• Acute deep vein thrombosis or pulmonary embolism (category 3).

Medicines to check. Potassium-sparing diuretics, aldosterone antagonists, ACE inhibitors, angiotensin receptor blockers, potassium supplements, heparin and long-term NSAIDs raise hyperkalaemia risk. Enzyme inducers (rifampicin, rifabutin, antiseizure inducers, efavirenz, ritonavir-boosted regimens, griseofulvin, St John’s wort) lower drospirenone levels: choose DMPA or an intrauterine device for long-term use.

Counselling. Consent, confidentiality, absence of coercion, condoms for infection protection, unpredictable bleeding. Adolescents under 18 years give assent.

Regimen.

• Drospirenone 4 mg tablet, orally, one tablet daily at the same time for 24 active days, then one inactive tablet daily for 4 days; start the next pack the day after the last tablet.
• Start on day 1 of menses without backup. Starting later (once pregnancy is excluded) needs backup for 7 days.
• Grace window: 24 hours.
• Missed active tablet over 24 hours late: take it at once, continue daily, use backup for 7 days, and consider emergency contraception if unprotected sex occurred in the last 5 days.
• Missed inactive tablets: discard; protection is unaffected.
• Vomiting within 3 to 4 hours of an active tablet counts as a missed tablet; severe diarrhoea over 2 days likewise.
• Switching from a hormonal method used correctly: start at once; from an injectable, when the repeat injection is due.
• No dose change for body weight.

Postpartum and after abortion. Breastfeeding women start from 6 weeks. Non-breastfeeding women start at once or within 3 weeks; later, exclude pregnancy and use backup for 7 days. Start at once after abortion.

Monitoring. Check blood pressure and bleeding concerns at review. Repeat potassium if new potassium-raising medicine is added. Review at least once a year.

Expected effects. Irregular or prolonged bleeding, amenorrhoea, acne, headache, breast tenderness, nausea, mood change.

Hyperkalaemia. Suspect with muscle weakness, palpitations or arrhythmia in a patient with renal impairment or potassium-raising drugs. Check serum potassium and ECG; stop the pill if potassium is raised and treat the hyperkalaemia.

Management of bleeding. Exclude pregnancy and gynaecological disease. Give ibuprofen 400 to 800 mg orally three times daily with food for 7 to 14 days, maximum 2400 mg in 24 hours, avoiding it in renal impairment, peptic ulcer, severe liver disease and NSAID-sensitive asthma. Persistent unacceptable bleeding means stopping and changing method.

Complications. Functional ovarian cysts. If pregnancy occurs, exclude ectopic pregnancy.

Red flags. Severe lower abdominal pain, calf swelling, chest pain, jaundice, breast lump, symptoms of high potassium.

Referral and escalation. Refer renal or adrenal disease for specialist review before continuing; refer abnormal bleeding for examination and cervical screening.