Levonorgestrel Teva (Levonorgestrel)

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

• Emergency contraception: Provides post‑coital protection when taken within a defined time after unprotected intercourse.
• Regular contraception: Used as a progestin‑only oral contraceptive to inhibit ovulation and alter the endometrium.
• Prevention of pregnancy: Serves as a component of combined hormonal regimens for ongoing birth control.

• Levonorgestrel binds to progesterone receptors in the hypothalamus and pituitary, suppressing the luteinizing hormone surge required for ovulation. It also induces changes in the cervical mucus and endometrial lining, reducing sperm penetration and preventing implantation of a fertilized ovum, thereby averting pregnancy.

Levonorgestrel is generally well tolerated, but several adverse reactions have been reported.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Headache: transient cranial discomfort.
• Fatigue: feeling of tiredness.
• Dizziness: occasional light‑headedness.
• Abdominal pain: cramping or discomfort.
• Menstrual changes: spotting or altered bleeding patterns.

Serious or Rare Side Effects

• Thromboembolic events: deep vein thrombosis or pulmonary embolism.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• Liver dysfunction: jaundice or elevated liver enzymes.
• Ectopic pregnancy: implantation outside the uterus.
• Persistent high blood pressure.
• Unexplained weight gain or edema.

Before prescribing Levonorgestrel, clinicians should consider several safety aspects.

• Assess contraindications: history of thromboembolic disorders, hormone‑sensitive cancers, or severe liver disease.
• Review medication history: avoid concurrent use with strong enzyme inducers that may reduce efficacy.
• Counsel on timing: effectiveness declines sharply after 72 hours for emergency use.
• Monitor menstrual patterns: advise patients to expect possible spotting or delayed periods.
• Advise on pregnancy testing: if menstruation is delayed beyond two weeks, a test is recommended.
• Store at ambient temperature: keep below 25 °C in the original packaging, protected from moisture and direct sunlight.

Levonorgestrel may interact with other medicines, altering its contraceptive reliability.

Major Interactions (Avoid)

• Rifampin and other potent CYP3A4 inducers: may markedly reduce plasma levels.
• St. John's wort: herbal inducer that can decrease effectiveness.
• Certain antiepileptic drugs (e.g., carbamazepine, phenytoin): may lower contraceptive protection.

Moderate Interactions (Monitor Closely)

• Antiretroviral agents (e.g., efavirenz): may modestly reduce efficacy.
• Antibiotics such as ampicillin: potential but limited impact, monitor cycle.
• Antifungal azoles (e.g., ketoconazole): may increase levonorgestrel levels, watch for side effects.
• Herbal supplements containing ginseng: possible interaction, advise caution.