Levonorgestrel Eg (Levonorgestrel)

Levonorgestrel acts on the hormonal pathway that regulates ovulation and implantation, providing contraceptive protection.

• Emergency contraception: prevents pregnancy after unprotected intercourse when taken within a defined time window.
• Regular contraception: maintains contraceptive efficacy as part of a combined or progestin‑only regimen for ongoing birth control.
• Menstrual cycle regulation: can be used to adjust timing of menstrual bleeding in certain clinical protocols.

• Levonorgestrel binds to progesterone receptors in the hypothalamus and reproductive tissues, inhibiting the luteinizing hormone surge that triggers ovulation. It also induces changes in cervical mucus, making it thicker and less penetrable to sperm, and alters the endometrial lining to reduce its receptivity for implantation. These combined actions suppress the possibility of fertilization and implantation. The drug’s oral absorption provides rapid plasma concentrations sufficient for emergency use.

Levonorgestrel may cause a range of adverse reactions, varying from mild to serious.

Common Side Effects

• Nausea: mild stomach upset.
• Headache: transient cranial pain.
• Breast tenderness: discomfort in breast tissue.

Serious or Rare Side Effects

• Thromboembolic events: blood clot formation.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• Liver dysfunction: abnormal liver enzymes or jaundice.

When prescribing Levonorgestrel, several precautions should be observed to ensure safe and effective use.

• Pregnancy testing: confirm the patient is not already pregnant before administration.
• Timing of intake: take the medication as soon as possible, preferably within 72 hours after unprotected intercourse.
• Drug interactions: avoid concomitant use with enzyme‑inducing agents that may lower effectiveness.
• Medical conditions: use with caution in patients with liver disease or a history of thromboembolic disorders.
• Age considerations: not recommended for women under 18 without medical supervision.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Levonorgestrel can interact with other medicines, affecting its contraceptive efficacy or safety.

Major Interactions (Avoid)

• Rifampicin: strong enzyme inducer that markedly reduces levonorgestrel plasma levels.
• Antiepileptic drugs (e.g., carbamazepine, phenytoin): decrease hormonal effectiveness.
• St. John’s wort: herbal inducer that may compromise contraceptive protection.

Moderate Interactions (Monitor Closely)

• Ketoconazole or other azole antifungals: may increase levonorgestrel concentrations.
• Certain antibiotics (e.g., tetracycline, metronidazole): can slightly reduce efficacy.
• Estrogen‑containing hormonal therapies: may alter overall hormonal balance.