Medroxyprogesterone Acetate — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Medroxyprogesterone Acetate?
Medroxyprogesterone acetate (MPA) is a synthetic progestogen used for contraception, HRT, endometriosis, and abnormal uterine bleeding. This medication is funded by Pharmac for contraception (Depo-Provera®) and gynaecological conditions.
What is Medroxyprogesterone Acetate Used For?
Medroxyprogesterone acetate (MPA) is used as injectable contraception (Depo-Provera®), as a component of oral combined HRT, for the management of endometriosis, secondary amenorrhoea, abnormal uterine bleeding, and as part of gender-affirming hormone therapy.
How Does Medroxyprogesterone Acetate Work?
MPA binds to progesterone receptors and has potent progestogenic, weak glucocorticoid, and weak androgenic activity. For contraception (Depo-Provera®): suppresses LH secretion, preventing ovulation, thickens cervical mucus, and induces endometrial atrophy.
How to Take Medroxyprogesterone Acetate
Depo-Provera® injection: 150 mg IM injection every 12 weeks (3 months). The first injection is given within 5 days of the start of a menstrual period. For HRT: oral MPA 2.5–10 mg/day cyclically or continuously. Oral tablets: 2.5 mg, 5 mg, 10 mg.
Common Side Effects of Medroxyprogesterone Acetate
- Irregular bleeding or spotting (common initially with Depo-Provera®)
- Amenorrhoea (absent periods — in up to 50–80% of users after 1 year)
- Weight gain
- Headache
- Mood changes
- Decreased libido
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Delayed return of fertility after stopping Depo-Provera® (can take 6–18 months)
- Decreased bone mineral density (with prolonged Depo-Provera® use — usually reversible after stopping; important consideration in adolescents)
- VTE (possible modest increased risk — lower than combined OCP)
- Depression
Drug Interactions
Medroxyprogesterone Acetate may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- Enzyme inducers (carbamazepine, rifampicin — may reduce efficacy of oral MPA but have less impact on Depo-Provera® due to high drug levels)
New Zealand Prescribing Information
Depo-Provera® (medroxyprogesterone acetate 150 mg/mL injection) is funded by Pharmac. It is one of the most popular injectable contraceptive methods in NZ. LARC (long-acting reversible contraception) counselling should include discussion of the delayed return to fertility and bone density effects, particularly in younger users. It does not protect against sexually transmitted infections.
Frequently Asked Questions
How quickly does Depo-Provera® wear off?
The injection provides contraceptive protection for 12–14 weeks. After the last injection, contraceptive effect can last up to 6–18 months — fertility return is significantly delayed compared to other contraceptives. This should be considered by women planning pregnancy in the near future.
Does the Depo-Provera® injection affect bone density?
Prolonged use of Depo-Provera® can reduce bone mineral density, particularly during adolescence when bones are still developing. Bone density typically recovers after stopping. The benefit-risk ratio is generally favourable for most women, but prolonged use (>2 years) should be reviewed, especially in adolescents.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: