Justine (Levonorgestrel)

Levonorgestrel is a progestogen used in the emergency contraception pathway to prevent unintended pregnancy.

• Emergency contraception: provides post‑coital contraceptive effect to reduce the chance of pregnancy when taken promptly after unprotected intercourse.
• Prevention of pregnancy: offers a short‑term hormonal method to avert implantation when used within the recommended time frame.
• Unintended pregnancy risk reduction: lowers the probability of conception in situations of contraceptive failure or missed doses.

• Levonorgestrel binds to progesterone receptors in the hypothalamic‑pituitary‑ovarian axis, suppressing the luteinizing hormone surge and thereby inhibiting or delaying ovulation. It also induces changes in the endometrial lining that reduce the likelihood of implantation should fertilization have occurred.

Levonorgestrel may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Abdominal pain: cramping or discomfort in the lower abdomen.
• Fatigue: feeling unusually tired or weak.
• Headache: mild to moderate head pain.
• Dizziness: sensation of light‑headedness.
• Menstrual changes: spotting, early or delayed periods.

Serious or Rare Side Effects

• Severe allergic reaction: rash, swelling, or difficulty breathing.
• Chest pain: unexplained discomfort in the chest area.
• Severe abdominal pain: intense or persistent pain that may indicate ectopic pregnancy.
• Vomiting blood or severe gastrointestinal bleeding.
• Signs of ectopic pregnancy: sharp pelvic pain with vaginal bleeding.
• Thromboembolic events: rare clotting disorders.

Levonorgestrel should be used with awareness of specific safety considerations.

• Timing of administration: take as soon as possible after unprotected intercourse for maximum effectiveness.
• Contraindications: avoid if known hypersensitivity to levonorgestrel or any tablet excipients.
• Medical conditions: caution in patients with active liver disease or uncontrolled hypertension.
• Drug interactions: review concomitant medications that may reduce efficacy, such as enzyme‑inducing agents.
• Pregnancy testing: not indicated for established pregnancy, but ensure the patient is not already pregnant before use.
• Store at ambient temperature: keep in the original packaging, protect from moisture and excessive heat.

Levonorgestrel may interact with other medicines, altering its effectiveness or safety profile.

Major Interactions (Avoid)

• Rifampicin: enzyme induction can markedly reduce levonorgestrel effectiveness.
• Antiepileptic enzyme inducers (e.g., carbamazepine, phenytoin): may lower plasma levels and compromise contraceptive protection.
• St. John’s Wort: herbal inducer that can diminish drug efficacy.

Moderate Interactions (Monitor Closely)

• Antifungal azoles (e.g., ketoconazole): may increase levonorgestrel concentrations.
• Protease inhibitor antiretrovirals: can affect metabolism and require monitoring.
• Hormonal contraceptives: concurrent use may lead to additive hormonal effects; assess risk‑benefit.