Za Pharmacy
Drugs, Supplies and Delivery
Marvelon (Desogestrel/Ethinylestradiol)
Marvelon is a combined oral contraceptive (COC) pill containing desogestrel (150 µg, a third-generation synthetic progestin) and ethinylestradiol (30 µg, a synthetic estrogen). Known for its high efficacy and favorable side effect profile, Marvelon is widely prescribed for contraception and menstrual regulation. This article explores its pharmacology, clinical applications, and safety profile, referencing authoritative sources such as the BNF, Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology.
Marvelon prevents pregnancy through multiple synergistic mechanisms:
- Ovulation Suppression: Ethinylestradiol inhibits follicle-stimulating hormone (FSH), preventing follicular development, while desogestrel blocks the luteinizing hormone (LH) surge, inhibiting ovulation (Lippincott).
- Cervical Mucus Alteration: Desogestrel thickens cervical mucus, creating a barrier to sperm penetration.
- Endometrial Changes: Progestin action thins the endometrial lining, reducing the likelihood of implantation (Lange).
Desogestrel, a third-generation progestin, has high selectivity for progesterone receptors with minimal androgenic activity, reducing side effects like acne and weight gain compared to older progestins.
- Contraception: Primary indication, with >99% efficacy when used correctly (BNF).
- Menstrual Cycle Regulation: Stabilizes cycles, reduces dysmenorrhea (painful periods), and treats menorrhagia (heavy bleeding).
- Acne Management: May improve mild to moderate acne due to desogestrel’s low androgenic activity (Lippincott).
- Standard Regimen: One tablet (150 µg desogestrel + 30 µg ethinylestradiol) daily for 21 days, followed by a 7-day hormone-free interval. Restart on day 8, regardless of bleeding (BNF).
- Initiation: Begin on day 1 of menstruation or the first Sunday thereafter. Backup contraception is recommended for the first 7 days.
- Missed Dose: If delayed <12 hours, take immediately. If >12 hours, follow BNF guidelines: Take missed pill ASAP, continue the pack, and use backup contraception for 7 days.
- Common: Nausea, headache, breast tenderness, mood changes, and breakthrough bleeding.
- Serious:
- Venous Thromboembolism (VTE): Slightly higher risk compared to second-generation progestins (e.g., levonorgestrel) (BNF).
- Cardiovascular Events: Increased risk in smokers >35 years or those with hypertension.
- Hepatic Effects: Rare hepatotoxicity, gallstones, or benign liver tumors (Lange).
- Absolute Contraindications: History of VTE, arterial thrombosis, estrogen-dependent cancers, severe liver disease, undiagnosed vaginal bleeding, or migraine with aura (BNF).
- Relative Precautions: Obesity, diabetes, hypertension, or familial hyperlipidemia.
- Monitoring: Regular blood pressure checks and screening for VTE risk factors (e.g., family history).
- Reduced Efficacy: Enzyme-inducing drugs (e.g., rifampicin, carbamazepine, St. John’s Wort) accelerate metabolism of ethinylestradiol, necessitating alternative contraception (BNF).
- Antibiotics: Limited evidence for interaction with broad-spectrum antibiotics (e.g., amoxicillin), but backup contraception is advised.
- Other Interactions: Avoid concurrent use with hepatotoxic drugs (e.g., acetaminophen overdose) or cyclosporine (desogestrel may increase plasma levels) (Lippincott).
- Active Ingredients: Desogestrel (150 µg) and ethinylestradiol (30 µg).
- Brands: Marketed as Marvelon; generics may be labeled as desogestrel/ethinylestradiol.
