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	Contraceptive

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, 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.

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.

It has similar chemical structure to mifepristone and is current under clinical trial in USA.
A small double-blind placebo-controlled clinical trial with oral daily 10 mg and 20 mg CDB-2914 for 3 months showed the following results:

• A reduction in total volume of fibroids of 17 % and 24 % for 10 mg and 20 mg dose of CDB-2914 over 3 months, respectively, while the size of fibroids in placebo group increased.
• Amenorrhoea occurred in 20 out of 26 patients in the CDB group and none in the placebo group.
• Overall Quality of Life was improved.

Long term effectiveness and tolerability are currently unknown.
Ref: Neiman et al. Fertility and Sterility; Nov 2010]
Recent media coverage on its possible application in fibroids is found in Nursingtimes.net. Further update on the clinical trial progress can be found by visiting ClinicalTrials.gov or Current Controlled Trials (UK) using term "CDB-2914" or "Ulipristal". Ulipristal is mainly evaluated as an emergency contraception.

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.