Levornorgestrel Sandoz Farmaceutica Lda. (Levonorgestrel)

Levonorgestrel is a synthetic progestogen used in hormonal contraception to prevent pregnancy.

• Emergency contraception: prevents pregnancy after unprotected intercourse by inhibiting or delaying ovulation.
• Regular contraception: maintains contraceptive efficacy when taken as directed in progestogen‑only regimens.
• Non‑estrogen contraceptive option: provides reliable birth control for women who cannot use estrogen‑containing products.

• Levonorgestrel binds to progesterone receptors in the hypothalamus and pituitary, suppressing the luteinizing hormone surge and thereby inhibiting ovulation. It also induces cervical mucus changes that impede sperm penetration and alters the endometrial lining, reducing the likelihood of implantation should fertilization occur.

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

Common Side Effects

• Nausea: mild stomach upset.
• Headache: tension‑type headache.
• Breast tenderness: mild discomfort.
• Irregular bleeding: spotting or changes in menstrual flow.

Serious or Rare Side Effects

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

When prescribing levonorgestrel, clinicians should consider several precautionary measures to ensure safe use.

• Contraindications: avoid in women with known hypersensitivity to levonorgestrel or other progestogens.
• Pregnancy status: not indicated for ongoing pregnancy; confirm negative pregnancy test before use.
• Breastfeeding: assess risk‑benefit; limited data, use only if clearly needed.
• Drug interactions: review concomitant medications that may reduce efficacy, such as enzyme inducers.
• Underlying conditions: caution in patients with active liver disease or thromboembolic disorders.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and light.

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

Major Interactions (Avoid)

• Rifampicin, carbamazepine, phenytoin, and St. John’s wort: strong enzyme inducers that markedly reduce levonorgestrel levels, risking contraceptive failure.
• Certain antiretrovirals (e.g., efavirenz): may lower plasma concentrations, compromising efficacy.

Moderate Interactions (Monitor Closely)

• Antifungal azoles (ketoconazole, itraconazole): may increase levonorgestrel exposure, potentially enhancing side effects.
• Anticonvulsants with moderate inducing effect (e.g., phenobarbital): may modestly reduce effectiveness.
• Hormonal therapies (e.g., estrogen‑containing contraceptives): may alter bleeding patterns but are generally safe.