Levonorgestrel Aristo (Levonorgestrel)

Levonorgestrel is a progestin used in hormonal contraception to prevent pregnancy.

• Emergency contraception: prevents pregnancy when taken shortly after unprotected intercourse.
• Prevention of pregnancy: used in progestin‑only or combined oral contraceptive regimens for ongoing birth control.
• Menstrual cycle regulation: may be prescribed to manage irregular bleeding associated with hormonal imbalance.

• Levonorgestrel binds to progesterone receptors in the hypothalamus and pituitary, suppressing the luteinizing hormone surge and thereby inhibiting ovulation. It also thickens cervical mucus, reducing sperm penetration, and induces endometrial changes that make implantation unlikely.

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

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Headache: tension‑type or migraine‑like pain.
• Abdominal pain: cramping or discomfort in the lower abdomen.
• Fatigue: feeling unusually tired.
• Breast tenderness: mild swelling or soreness.
• Menstrual changes: spotting, heavier or lighter bleeding.

Serious or Rare Side Effects

• Allergic reaction: rash, itching, swelling, or anaphylaxis.
• Severe abdominal pain: could indicate ectopic pregnancy.
• Blood clotting disorders: deep vein thrombosis or pulmonary embolism.
• Liver dysfunction: jaundice or elevated liver enzymes.
• Mood disturbances: severe depression or anxiety.
• Vision changes: blurred vision or visual disturbances.

Before using Levonorgestrel, consider the following safety measures.

• Contraindications: avoid if known hypersensitivity to levonorgestrel or other progestins.
• Medical history: review for liver disease, clotting disorders, or hormone‑sensitive cancers.
• Drug interactions: assess concurrent use of enzyme‑inducing medications.
• Missed dose: follow specific guidance on timing to maintain efficacy.
• Pregnancy testing: ensure the patient is not already pregnant before administration.
• Store at ambient temperature: keep in the original packaging, protect from moisture and direct sunlight.

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

Major Interactions (Avoid)

• Rifampin: reduces plasma levels, decreasing contraceptive efficacy.
• Carbamazepine: enzyme inducer that may lower drug concentration.
• Phenytoin: similar enzyme‑inducing effect.
• St. John’s wort: herbal inducer that can compromise effectiveness.
• Certain antiretrovirals (e.g., efavirenz): may diminish contraceptive protection.

Moderate Interactions (Monitor Closely)

• Ketoconazole: may increase levonorgestrel levels, raising side‑effect risk.
• Antifungal azoles: potential for modest plasma concentration changes.
• Antidepressants (SSRIs): monitor for mood alterations.
• Hormonal therapies: assess combined hormonal effects.
• Antibiotics (e.g., rifabutin): observe for reduced efficacy.