Medroxyprogesterone vs Norethindrone: side-by-side comparison
Medroxyprogesterone and Norethindrone belong to the same class (Progestin). They share therapeutic approach but differ in mechanism nuances, half-life, side-effect profile and available formulations. This comparison summarises what is common and where they diverge.
| Property | Medroxyprogesterone | Norethindrone |
|---|---|---|
| Therapeutic class | Progestin | Progestin |
| CAS | 520-85-4 | 68-22-4 |
| ATC | G03DA02 | G03DC02 |
| Molecular weight | 344.49 g/mol | 298.42 g/mol |
| Brands with this active ingredient | 1 | 1 |
What they share
Both are in the Progestin class, giving them a common pharmacological architecture and many shared safety and management points. Choice within the class comes down to mechanism nuances, half-life, side-effect profile and individual response.
Key differences
Differences within the Progestin class are what matter in practice: half-life, route of administration, equivalent doses, specific interactions, predominant side-effect profile and accumulated clinical experience. This page frames them; the prescribing information gives quantitative detail.
Mechanisms compared
Medroxyprogesterone: MPA binds progesterone receptors and produces strong progestational effects: thickening cervical mucus, inhibiting ovulation, thinning the endometrium and reducing hot flashes. Norethindrone: Norethindrone binds to progesterone receptors and exerts progestational effects: thickening cervical mucus, suppressing the LH surge, thinning the endometrium and inhibiting ovulation (at sufficient doses).
Indications compared
Medroxyprogesterone: MPA is approved for amenorrhoea, abnormal uterine bleeding due to hormonal imbalance, prevention of endometrial hyperplasia in postmenopausal women receiving estrogen, and prevention of pregnancy (depot formulation). Norethindrone: Norethindrone is approved for prevention of pregnancy (progestin-only and combined formulations), secondary amenorrhoea, abnormal uterine bleeding, endometriosis-associated pain, and as part of menopausal hormone replace…
Safety profile
Medroxyprogesterone: Common adverse effects of oral MPA include irregular bleeding, breast tenderness, mood changes, fluid retention and weight gain. Norethindrone: Common adverse effects include breakthrough bleeding, breast tenderness, nausea, mood changes and headache.
Frequently asked questions
Is Medroxyprogesterone better than Norethindrone? ▾
Neither is universally better. Medroxyprogesterone and Norethindrone share the Progestin class but differ in half-life, mechanism nuances and side-effect profile. The choice depends on the patient and the prescriber.
Can Medroxyprogesterone and Norethindrone be combined? ▾
Combining two ingredients from the same Progestin class is uncommon and, in most cases, adds no benefit over one at an appropriate dose. The decision is always the prescriber's.
Do they have the same side-effect profile? ▾
Partly yes — they share many Progestin class effects, with nuances by mechanism and dose. The prescribing information lists differences.
Products with Medroxyprogesterone
Products with Norethindrone
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.