Lethe (Drospirenone, Ethinylestradiol | Lactose Anhydrous)

Lethe, a combined oral contraceptive, works within the hormonal contraceptive pathway to prevent unintended pregnancy and to manage menstrual‑related conditions.

• Prevention of pregnancy: provides reliable contraception by inhibiting ovulation and altering cervical mucus.
• Regulation of menstrual cycles: stabilizes cycle length and reduces irregular bleeding.
• Endometriosis symptom control: lessens pelvic pain and suppresses lesion growth through hormonal modulation.

• Drospirenone is a synthetic progestogen with anti‑mineralocorticoid and anti‑androgenic activity, while ethinylestradiol is a synthetic estrogen. Together they bind to progesterone and estrogen receptors, suppressing the hypothalamic‑pituitary release of luteinizing hormone (LH) and follicle‑stimulating hormone (FSH). This inhibition prevents follicular development and ovulation. The combination also thickens cervical mucus and induces endometrial changes that reduce the likelihood of fertilisation and implantation.

Lethe may cause a range of adverse reactions, which are generally classified by frequency and severity.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Headache: tension‑type or migraine‑like pain.
• Breast tenderness: swelling or discomfort.
• Irregular bleeding or spotting: breakthrough bleeding between periods.

Serious or Rare Side Effects

• Venous thromboembolism: deep‑vein thrombosis or pulmonary embolism.
• Stroke: cerebrovascular accident, especially in high‑risk patients.
• Severe hypertension: sudden increase in blood pressure requiring medical attention.

When prescribing Lethe, clinicians should consider several precautionary measures to minimise risk.

• Pregnancy contraindication: do not use in women who are or may become pregnant.
• Smoking restriction: avoid in women over 35 who smoke more than 15 cigarettes per day.
• History of thromboembolism: contraindicated in patients with prior venous or arterial clotting events.
• Liver disease: use with caution in severe hepatic impairment.
• Hypertension: monitor blood pressure regularly and discontinue if uncontrolled.
• Store below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Lethe can interact with other medicines, altering its effectiveness or safety profile.

Major Interactions (Avoid)

• Enzyme inducers (e.g., rifampin, carbamazepine, phenytoin, St. John’s wort): markedly reduce contraceptive efficacy.
• Certain antiretrovirals (e.g., efavirenz): may lower plasma levels of ethinylestradiol.
• Strong CYP3A4 inhibitors (e.g., ketoconazole) when combined with high‑dose estrogen: increase risk of estrogen‑related adverse events.

Moderate Interactions (Monitor Closely)

• Antibiotics (e.g., macrolides, tetracyclines): may slightly diminish contraceptive effect.
• Antifungals (e.g., itraconazole): can raise hormone concentrations, requiring blood pressure monitoring.
• Selective serotonin reuptake inhibitors (e.g., fluoxetine): may increase bleeding tendency.
• Herbal supplements (e.g., ginseng): potential modest reduction in effectiveness.