Unipill 1.5mg

Indications

• Emergency contraception
• Hormonal contraception (combined with estrogens or as a progestin-only method)
• Management of menstrual disorders
• Endometrial protection in hormone replacement therapy

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations and guidance.

Adults: Refer to specific guidelines for dosing based on the indication; typically, for emergency contraception, a single dose of 1.5 mg is administered as soon as possible after unprotected intercourse.

Mechanism of action

Levonorgestrel works by binding to progesterone receptors in the body, leading to the inhibition of ovulation and alterations in the cervical mucus and endometrial lining. This hormonal action prevents sperm from reaching the egg and reduces the likelihood of implantation of a fertilized egg.

Pharmacodynamics

Levonorgestrel exhibits progestational activity, which influences the menstrual cycle and alters the endometrium. It helps in thickening the cervical mucus, making it less permeable to sperm. The drug also affects the hypothalamic-pituitary-gonadal axis, leading to reduced secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), thereby inhibiting ovulation.

Pharmacokinetics

Levonorgestrel is well absorbed from the gastrointestinal tract and undergoes extensive first-pass metabolism in the liver. Its bioavailability is approximately 100% when administered as an intrauterine device (IUD) or through injection. The drug has a half-life of about 24 hours, with peak plasma concentrations occurring within 1 to 2 hours after oral administration. Levonorgestrel is primarily metabolized in the liver, with metabolites excreted mainly in urine and feces.

Contra-indications

• Known or suspected pregnancy
• Severe liver disease
• History of thromboembolic disorders
• Undiagnosed genital bleeding
• Hypersensitivity to levonorgestrel or any component of the formulation

Adverse effects

• Nausea
• Vomiting
• Fatigue
• Headache
• Dizziness
• Breast tenderness
• Abdominal pain
• Changes in menstrual bleeding patterns

Interactions

• Anticonvulsants (e.g., phenytoin, carbamazepine) may reduce effectiveness
• Rifampicin and other rifamycins can decrease levonorgestrel plasma levels
• Certain herbal supplements (e.g., St. John's Wort) may affect metabolism

Precautions

• Monitor for signs of ectopic pregnancy
• Consider alternative contraceptive methods for individuals with gastrointestinal issues affecting absorption
• Use with caution in patients with a history of depression

Pregnancy

Levonorgestrel is not indicated during pregnancy and is contraindicated if pregnancy is confirmed.

Breast-feeding

Levonorgestrel is excreted in breast milk, but is considered safe for use during breastfeeding. Monitoring for adverse effects in infants is advisable.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Oral tablet
• Intrauterine device (IUD)