Spironolactone is another medication commonly used in gender-affirming care, particularly for transgender women (assigned male at birth) or those with androgen-dependent conditions. It is primarily used as an anti-androgen to suppress testosterone levels and aid in feminisation. However, like any medication, it comes with potential unwanted/adverse/side effects. Here are some of them:
| Side Effect | Description |
| Electrolyte imbalance | Spironolactone is a potassium-sparing diuretic, meaning it can cause the body to retain potassium. This can lead to hyperkalemia, which is elevated potassium levels in the blood. Hyperkalemia can be serious and even life-threatening, causing symptoms such as weakness, irregular heartbeat, and paralysis. |
| Dehydration and electrolyte disturbances | While retaining potassium, spironolactone can also cause the loss of sodium and water through increased urination, potentially leading to dehydration and electrolyte imbalances if not properly monitored. |
| Hypotension (low blood pressure) | Spironolactone can lower blood pressure, leading to symptoms such as dizziness, lightheadedness, or fainting, particularly when standing up quickly. This effect is more pronounced in individuals with already low blood pressure or those taking other medications that lower blood pressure. |
| Increased urination | Spironolactone is a diuretic, so increased urination (polyuria) is a common side effect. This can disrupt sleep patterns or cause inconvenience during the day. |
| Breast tenderness and enlargement | Similar to cyproterone acetate, spironolactone can cause breast tenderness and enlargement due to its anti-androgenic effects. This effect is often desired in transgender women but may cause discomfort in some individuals. |
| Decreased libido | Some individuals may experience a decrease in libido (sex drive) while taking spironolactone. |
| Menstrual irregularities | In transgender women or individuals with androgen-dependent conditions, spironolactone may cause changes in menstrual patterns, including irregular bleeding or cessation of menstruation. |
| Gynecomastia | Spironolactone can cause breast development (gynecomastia) in individuals assigned male at birth, which may be desired but can also cause distress in some cases. |
| Digestive issues | Spironolactone can cause gastrointestinal symptoms such as nausea, vomiting, diarrhea, or stomach cramps in some individuals. |
| Headache | Headaches are a common side effect of spironolactone use. |
| Allergic reactions | Although rare, some individuals may experience allergic reactions to spironolactone, including rash, itching, swelling, or difficulty breathing. Immediate medical attention is necessary if any signs of an allergic reaction occur. |