Primalut N Tablet Composition
Primalut N contains norethisterone (also called norethindrone) as its active ingredient, typically formulated as 5 mg tablets of norethisterone or norethisterone acetate, which is a synthetic progestogen derived from 19-nortestosterone. 1
Active Pharmaceutical Ingredient
- Norethisterone (norethindrone) is the sole active component, classified as a normethyltestosterone derivative progestin with mild androgenic activity 1
- The standard formulation contains 5 mg norethisterone per tablet, though 10 mg formulations also exist for specific indications 1
- Norethisterone belongs to the estrane group of 19-nortestosterone derivatives, distinguishing it from progesterone-derived progestins 2
Inactive Ingredients (Typical Formulation)
Based on norethisterone tablet formulations, inactive ingredients commonly include: 3
- Corn starch
- Lactose anhydrous
- Microcrystalline cellulose
- Povidone
- Magnesium stearate
- Sodium starch glycolate
- Talc
- Ethyl cellulose
- Coloring agents (may vary by manufacturer)
Pharmacological Classification
- Norethisterone is a synthetic progestogen with potent antigonadotropic properties when used at doses of 5-10 mg daily 1
- At therapeutic doses (5-15 mg daily), it functions as a potent antigonadotropic agent with mild androgenic activity, distinguishing it from pure progestational molecules 1, 2
- Unlike natural progesterone, norethisterone can display metabolic and vascular side effects related to its androgenic potency, though these are less pronounced than with danazol 1
Clinical Dosing Context
- For menstrual regulation and hormonal imbalances, norethisterone is typically prescribed at 5 mg daily for 10-14 days per cycle 1
- For menstrual suppression (such as during chemotherapy or thrombocytopenia), doses of 5-15 mg daily continuously may be used, though higher doses carry increased thrombotic risk 4
- For hormone replacement therapy, norethisterone acetate 1 mg daily provides adequate endometrial protection with a superior cardiovascular profile compared to higher doses 1, 4
Important Pharmacological Distinctions
- Norethisterone differs fundamentally from natural micronized progesterone, which has a more favorable cardiovascular and metabolic safety profile 1, 4
- The androgenic properties of norethisterone can cause adverse effects on lipid profiles, vasomotion, and blood pressure, particularly when combined with ethinyl estradiol rather than natural estradiol 1
- Norethisterone acetate (the acetate ester form) has enhanced oral bioavailability compared to natural progesterone but maintains similar androgenic effects 1, 2