British Fibroid Trust Woman2Woman Fibroid Support Fibroids: Patient Guide
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Medical Therapy
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Medical therapy can in some cases reduce the need for an operation but often it is not a long term solution. The drugs used can be divided into 2 groups: oral non-hormonal and hormonal (in various formulations). Summary of the available choices for medical therapy is shown below:

Summary: Medical Therapy
Type of Drug Product Outcome on fibroid size Outcome on abnormal uterine bleeding Outcome on fertility
Non-Hormonal NSAIDs
& Tranexamic Acid
No effect on fibroid size Decrease by 30% No effect
Hormonal Combined Oral Contraceptive No data Decrease 20-30% Contraceptive
GnRHa (3 to 6 months duration of therapy) Decrease 30%
Decrease uterine volume by 35%
Decrease > 80% Contraceptive
Oral Progestins Decrease 30% Decrease > 60% Contraceptive
LARC (Long Acting Reversible Contraceptive (e.g. Depo-Provera, Implanon [etonogestrel]) Decrease uterine volume by 35% Breakthrough bleeding Contraceptive
Levonorgestrel Intrauterine Device (e.g. Mirena) Decrease 20-30 % Decrease 40%
Systemic side effects
GnRH (Gonadotropin releasing hormone) agonist & antagonist

Key features of GnRH treatments
GnRH Agonist GnRH Antagonist
  • It reduces oestrogen and progesterone levels and blood flow to the fibroids to shrink them. It works by temporarily stopping the menstrual periods and put you in the menopausal state.
  • Often, GnRHa treatment is given 3 to 4 months to shrink the fibroids before myomectomy or hysterectomy (in order to avoid midline incision, anaemia, blood transfusion), and also as a "short-term" treatment for women nearing the menopause (i.e. late peri-menopause) to reduce the bulk. Clinical evidence showed that up 30% reduction in fibroid size was achieved after a 6 month treatment of GnRHa.
  • A temporary treatment only: Once GnRHa treatment stops, the fibroids will return to their former (original) size.
  • GnRHa also reduces blood loss and relieves pelvic pressure, urinary frequency, nocturia and constipation.
  • The most commonly prescribed GnRHa is Zoladex which is injected either every month or 3-monthly and can be given up to 6 months maximum.
  • The major side-effect is severe bone thinning leading to osteoporosis. Some clinicians prescribe tibilone, raloxifene as "add-back" to minimise this bone loss.
  • Other adverse effects include symptoms of menopause (hot flushes, headache and vaginal dryness), irregular bleeding, depression, hair loss and musculoskeletal stiffness.
  • Reduction in fibroid size occurs more quickly compared to GnRH agonist.
  • Commonly, it is used as pre-operative in young women and before peri-menopausal women.
  • A typical example: Cetrorelix.
  • Side effects include hot flushes, amenorrheic (absence of menstrual periods). Normal periods return within one month of discontinuation of treatment.
  • Short term therapy only.
  • Fibroid regrows after stopping the medication.
Male hormones (androgens)

They can slow or stop the growth of fibroids and offer symptoms relief. Drugs like Danazol can reduce the size of the fibroids and the womb, and stop the periods and anaemia. However, its side-effects are off-putting for many women. The side-effects include weigh gain, depression, anxiety, oily skin and hair, deepening of the voice, headache, fatigue, hair loss, growth of facial and body hair, blood clots and liver problems.
Exogenous progestins

Exogenous progestins, taken orally, are often used to reduce bleeding but have no effect on fibroid size.
(a) Medroxy-progesterone acetate (Provera) 5-10 mg once a day, or (b) Megestrol acetate 10-20 mg daily.
Either one is prescribed in the first 10-14 days of the menstrual cycle. Usually, bleeding is regulated after 1-2 cycles.
Provera can also be administered as a single injection (150 mg intramuscular) once every 3 months (Depo-Provera). It is best to see first whether you show any adverse side effects (weigh gain, depression, and even irregular bleeding) to the oral dose before trying the injection, because the effect of one injection lasts three months.
Medicated IUS
  • Medicated IUS is only suitable for heavy bleeding caused by fibroids with the fibroid uterus (womb) size of less than 12-week pregnancy with no distorting intracavity fibroids.
  • Mainly, IUS treats heavy period symptoms.
  • The procedure involves inserting an IUS (coil) into the uterus. This device delivers the hormone to decrease the blood flow to the fibroid preventing it developing.
    It has not been proven effective in reducing the size of the fibroids.
  • It may reduce your chance of requiring surgery or other medical treatment.
  • Side effects include irregular bleeding which can last up to six months, acne, headache, breast tenderness and in rare cases your period may stop altogether.
  • MIRENA® is the most commonly fitted coil in UK for control of heavy bleeding in fibroid patients. It does NOT reduce the fibroid size.
    It is a plastic coil which slowly releases levonorgestrel into the womb. Mirena coil can only used in women with fibroid uteri (womb) that is not more than 12 weeks pregnancy size. At the time of writing, Mirena is only licensed for heavy menstrual bleeding and NOT for fibroid treatment.
Newly Approved Therapy

Ulipristal- ESMYA®

Previously, it was known as CDB-2914. It has similar chemical structure to mifepristone.

Two recent clinical trials (PEARL 1, PEARL 2, published February 2012) showed ulipristal acetate, at a daily dose of 10 mg, to achieve reduction in fibroid size (42 %) and improvement in heavy menstrual bleeding (98 % reduced heavy periods, 89 % amenorrhoea/no periods) comparable to that achieved by GnRHa (Leuprolide Acetate, Prostap). A daily dose of 5mg ulipristal appears to marginally less effective than the 10 mg dose at achieving fibroid size reduction (36 %) and amenorrhoea (75 %), but these differences are not statistically significant.

Importantly, ulipristal was able to achieve symptom improvement by one week of treatment commencement (compared to three weeks for GnRHa) and had significantly less side effects than GnRHa (i.e. 10 % risk of hot flushes compared to 40 % risk of hot flushes with GnRHa).
In March 2012, Ulipristal received a European wide medical licence permitting its use as a medical treatment of fibroids.

Donnez et al. Ulipristal acetate versus leuprolide acetate for uterine fibroids. The New England Journal of Medicine: Feb 2012, Vol 366, 421-431.
Donnez et al. Ulipristal acetate versus placebo for fibroid treatment before surgery. The New England Journal of Medicine: Feb 2012, Vol 366, 409-420.
Neiman et al. Fertility and Sterility; Nov 2010
Media coverage on its possible application in fibroids is found in

Under TRIAL medical therapy

Summary: Under TRIAL Medical Therapy
Product Outcome on fibroid size Outcome on heavy menstrual bleeding
SPRM: Mifepristone (RU486) Decrease uterine volume by 40% Decrease (but small risk of endometrial hyperplasia)
SPRM: Asoprisnil, Proellex® Decrease by 35 - 40 % Decrease
SERM: ormeloxifene Unknown Decrease
Oral progestogen: dienogest Unknown May decrease
GnRHa: Ganirelix (subcutaneous Injection) Decrease by 30 - 40 % Decrease
Aromatase Inhibitors: Anastrozole, Letrozole Decrease Decrease
Keys: SPRM: Selective progesterone receptor modulator
SERM: Selective estrogen receptor modulator.

Doses of Mifepristone 5 - 50 mg daily in clinical trials over 6 months show significant decrease in symptom severity and increase in quality of life questionaire.
Major side-effects for Mifepristone include cystic granular dilation of the endometrium, hot flushes, headache, nausea, mood swings, diarrhoea, decreased libido, weakness, fatigue, endometrial hyperplasia (thickening) and increased liver enzymes.Long term effectiveness and tolerability are currently unknown.
Doses of Asoprisnil 5-25 mg/daily in clinical trials in 129 women with fibroids show dose dependent reduction in uterine bleeding with 70% women in dose group 25mg/daily becoming amennorhea.
Side-effects for Asoprisnil include bloating, flatulence, breast pain, hot flushes and night sweats.There are some incidences of asymptomatic ovarian cysts. Long term effectiveness and tolerability are currently unknown.
Anastrozole is an aromatase inhibitor. At 1 mg daily orally for 3 months, in a trial of 20 patients, it is shown to be effective in reducing the volume of fibroids by an average of 9.32 % (up to 32 %) leading to the control of symptoms without changes in hormone levels (FSH and estradiol).
[Ref: Sandro G. Hilário et al. Fertility and Sterility; Volume 91(1) January 2009, Pages 240-243].
There is no long-term data or data on large trials available at the moment.
It is an aromatase inhibitor. Currently, it is licenced for use in breast cancer. In fibroids, a clinical trial study shows, with 5 mg daily orally for 3 months, reduction in the size of fibroids and improvement in heavy menstrual bleeding symptom without changing bone mineral density (i.e low risk of osteoporosis).
[Ref: Bilgin Guratesa et al. Reproductive BioMedicine Online Volume 17, Issue 4, 2008, Pages 569-574].
In another study with 70 patients, at a dose of 2.5 mg daily for 12 weeks on fibroids greater than 5 cm, 45.6 % reduction in the volume of fibroids was reported.
[Ref: Mohammad Ebrahim Parsanezhad et at. Fertility and Sterility; Volume 93(1), January 2010, Pages 192-198].
So far there are encouraging clinical trial data for letrozole use in fibroids but the long-term data is still lacking and further investigations are needed.
Author: Dr Nicki On, PhD, MRPharmS.
The information on this page has been peer-reviewed by
Dr Rajesh Varma, MA, PhD, MRCOG. Dept of Obstetrics and Gynaecology, Guy's and St. Thomas' NHS Foundation Trust, London SE1 7EH, UK.

This website provides primarily information which is intended for educational purpose only. All contents within British Fibroid Trust should not be treated as a substitute for the medical advice of your own doctor or gynaecologist or any other health care professional. Medical decisions must be made in consultation with a qualified gynaecologist or specialist based on a complete medical history, physical examination and diagnostic results.
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This page was last modified on Monday 1 February 2021 11:57 am.
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