From the Guidelines
Spironolactone can cause menstrual irregularities in 15-30% of patients, with the risk being dose-dependent, as evidenced by a relative risk of 4.12 (95% CI 3.27-5.19) in women receiving a dose of 200mg/day compared to those receiving lower doses 1.
Mechanism and Side Effects
The medication works as an anti-androgen, disrupting the hormonal balance that regulates menstrual cycles, leading to common period-related side effects such as irregular periods, spotting between periods, heavier bleeding, or occasionally missed periods. These effects are due to spironolactone's ability to block androgen receptors and inhibit testosterone production, altering the estrogen-progesterone balance that controls the menstrual cycle.
Management and Recommendations
The concomitant use of a combined oral contraceptive (COC) or hormonal intrauterine device can minimize the incidence of menstrual irregularities caused by spironolactone 1. If troublesome menstrual irregularities occur while taking spironolactone, consulting a healthcare provider is recommended, as they may adjust the dosage or recommend hormonal contraceptives to help regulate the menstrual cycle while continuing treatment.
Key Considerations
- The side effects are typically reversible once the medication is discontinued.
- For women using spironolactone for acne or hirsutism, these side effects often diminish after several months of use as the body adjusts to the medication.
- Potassium monitoring is not required in young, healthy women without risk factors for hyperkalemia, but should be considered in those with risk factors such as renal insufficiency or severe heart failure 1.
From the Research
Spironolactone and Menstrual Irregularities
- Spironolactone has been associated with menstrual abnormalities, including intermenstrual bleeding, in women with polycystic ovary syndrome (PCOS) 2.
- A study found that spironolactone reduced serum estradiol and endometrial thickness in PCOS patients, which may contribute to menstrual irregularities 2.
- Another study reported that spironolactone caused spotting in one-third of the treatment cycles, but had a slight effect on regularizing menstruation 3.
Effects of Spironolactone on Hormonal Balance
- Spironolactone has been shown to affect hormonal balance, including reducing androgen levels and increasing estrogen levels 3, 4.
- A study found that spironolactone may cause hormonally associated vestibulodynia and female sexual arousal disorder due to its effects on estrogen and testosterone levels 5.
Comparison with Other Treatments
- Spironolactone has been compared to other treatments, such as combined oral contraceptive pills (COC) and metformin, in the management of PCOS 4, 6.
- A systematic review found that spironolactone alone or in combination with other drugs is safer than COC, but COC treats more PCOS-associated symptoms, including acne and menstrual irregularities 4.
- A randomized clinical trial found that COC plus spironolactone was more effective than metformin in improving symptoms of PCOS, including hirsutism and menstrual dysfunction 6.