Norethisterone Remedica (Norethisterone)

Norethisterone is a synthetic progestogen that acts on the hormonal regulation of the menstrual cycle and ovulation.

• Menstrual disorders: helps regulate irregular cycles and reduces heavy bleeding.
• Endometriosis: alleviates pain and suppresses ectopic endometrial tissue growth.
• Contraception: provides progestogenic activity to prevent ovulation when used in appropriate regimens.
• Secondary amenorrhea: induces withdrawal bleeding in women with absent menstrual periods.

• Norethisterone binds selectively to progesterone receptors in the hypothalamic‑pituitary‑ovarian axis, inhibiting the luteinising hormone surge and thereby preventing ovulation. It also induces endometrial transformation that stabilises the uterine lining, reducing menstrual bleeding and ectopic endometrial growth.

Norethisterone may cause a range of adverse reactions, most of which are dose‑related and reversible upon discontinuation.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Breast tenderness: discomfort or swelling of breast tissue.
• Headache: occasional tension‑type headache.
• Weight gain: modest increase in body weight.
• Mood changes: irritability or mild depressive symptoms.
• Irregular bleeding: spotting or breakthrough bleeding.

Serious or Rare Side Effects

• Venous thromboembolism: deep vein thrombosis or pulmonary embolism.
• Hepatic dysfunction: jaundice or elevated liver enzymes.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• Depression: worsening of mood disorders.
• Hypertension: new‑onset high blood pressure.
• Visual disturbances: rare reports of blurred vision.

Before initiating therapy with Norethisterone, clinicians should consider several safety aspects.

• Assess thrombotic risk: avoid in patients with a history of clotting disorders.
• Evaluate liver function: contraindicated in active hepatic disease.
• Review contraindications: not for use in known hypersensitivity to progestins.
• Monitor blood pressure: watch for hypertension during treatment.
• Counsel on smoking: advise cessation, especially in women over 35.
• Store at room temperature: keep in original packaging, protect from moisture and direct sunlight.

Norethisterone can interact with other medicines that affect its metabolism or hormonal activity.

Major Interactions (Avoid)

• Rifampicin: strong enzyme inducer that reduces plasma levels.
• Anticonvulsants (e.g., carbamazepine, phenytoin): lower effectiveness of the progestin.
• Antiretrovirals (e.g., efavirenz): may diminish contraceptive efficacy.
• St. John’s wort: herbal inducer that decreases drug exposure.
• Certain antifungals (e.g., ketoconazole): can increase levels, raising risk of side effects.

Moderate Interactions (Monitor Closely)

• Warfarin: may alter anticoagulant control.
• Antidiabetic agents: possible effect on glucose tolerance.
• Thyroid hormones: monitor thyroid function tests.
• Antibiotics (e.g., tetracycline): rare reports of reduced contraceptive effect.
• SSRIs: watch for mood changes.