1. Clinical Overview
A fixed-dose, monophasic combined oral contraceptive (COC) pill containing a synthetic estrogen (Ethinyl Estradiol) and a second-generation progestin (Levonorgestrel). It is one of the most widely prescribed and studied COCs globally and in India, primarily used for pregnancy prevention. It works by inhibiting ovulation, thickening cervical mucus, and altering the endometrium.
| Onset | Duration | Bioavailability |
|---|---|---|
| Inhibition of ovulation begins with the first dose, but full contraceptive efficacy is achieved after 7 consecutive days of correct use. Cervical mucus thickening occurs within hours. | Approximately 24 hours for each dose. The contraceptive effect is maintained only with daily, continuous administration. | Ethinyl Estradiol: ~40-50% (extensive first-pass metabolism). Levonorgestrel: ~100% (almost completely bioavailable). |
2. Mechanism of Action
The primary mechanism is suppression of the hypothalamic-pituitary-ovarian axis. Ethinyl Estradiol suppresses follicle-stimulating hormone (FSH) secretion, inhibiting follicular development. Levonorgestrel suppresses luteinizing hormone (LH) surge, preventing ovulation. Secondary mechanisms include progestin-induced thickening of cervical mucus (impeding sperm penetration) and creation of an endometrial environment unsuitable for implantation.
3. Indications & Uses
- Prevention of pregnancy (Contraception)
- Treatment of heavy menstrual bleeding (Menorrhagia) in the absence of pathology
- Management of menstrual cycle irregularities
4. Dosage & Administration
Adult Dosage: One tablet (0.03mg EE + 0.15mg LNG) orally once daily, preferably at the same time each day. For contraception: Start on Day 1 of menstrual cycle (no backup needed) or on Sunday after period begins (backup needed for first 7 days). Follow a 21-day active pill/7-day pill-free regimen.
Administration: Take with or without food. If a pill is missed (<24 hours late), take it as soon as remembered and next pill at regular time. If >24 hours late, follow specific missed pill guidelines (use backup contraception). For vomiting/diarrhea within 3-4 hours of intake, consider it a missed pill.
5. Side Effects
Common side effects may include:
- Nausea, vomiting
- Headache (including migraine)
- Breast tenderness, enlargement
- Breakthrough bleeding, spotting (especially in first 3 cycles)
- Amenorrhea or changes in menstrual flow
- Weight change
- Mood changes, depression
- Acne
- Decreased libido
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Enzyme Inducers (Rifampicin, Rifabutin, Carbamazepine, Phenytoin, Phenobarbital, Primidone, Topiramate, Modafinil, St. John's Wort) | Marked decrease in contraceptive efficacy due to increased metabolism of EE and LNG. Risk of unintended pregnancy. | Major |
| Broad-spectrum Antibiotics (e.g., Ampicillin, Tetracyclines, Griseofulvin) | Possible reduction in efficacy due to disruption of enterohepatic recirculation of EE. Evidence is controversial but backup contraception is advised. | Moderate |
| Antiretroviral Protease Inhibitors & NNRTIs (e.g., Ritonavir, Nevirapine, Efavirenz) | Altered levels of contraceptive hormones; may increase or decrease efficacy. | Major |
| Warfarin and other Coumarins | EE may alter coagulation factors; progestins may antagonize anticoagulant effect. Monitor INR closely. | Moderate |
| Cyclosporine | EE may inhibit metabolism, increasing Cyclosporine levels and toxicity risk. | Moderate |
| Lamotrigine | EE significantly reduces Lamotrigine serum levels, increasing risk of seizures. Dose adjustment of Lamotrigine may be needed. | Major |
| Tizanidine | EE may inhibit CYP1A2, increasing Tizanidine levels and risk of hypotension/bradycardia. | Moderate |
| Selegiline | Increased risk of hypertension when combined with EE. | Moderate |
| Ascorbic Acid (High Dose) and Paracetamol | May increase plasma levels of EE by competing for conjugation. | Minor |
7. Patient Counselling
- DO take the pill at the same time every day to maintain efficacy.
- DO use a backup contraceptive method (e.g., condoms) for the first 7 days of the first cycle or if you miss a pill.
- DO inform any doctor, surgeon, or pharmacist that you are taking this pill.
- DO have regular medical check-ups including BP monitoring.
- DONT smoke cigarettes, especially if you are 35 or older.
- DONT take this pill if you are pregnant or suspect pregnancy.
- DONT use this pill to protect against HIV/AIDS or other sexually transmitted infections.
8. Toxicology & Storage
Overdose: Nausea, vomiting, drowsiness, fatigue, and withdrawal bleeding in females. No specific serious acute toxicity is expected from ingestion of a few tablets. In children, estrogen overdose may cause nipple discharge and gynecomastia.
Storage: Store below 30°C. Protect from light and moisture. Keep in the original blister pack. Keep out of reach of children.