Medical Treatment of Endometriosis

Whilst medical therapies can reduce some of the pain associated with endometriosis in patients with minimal endometriosis they are not effective in the long term treatment of most patients of endometriosis as:

  • They are often poor at reducing pain, in particular in patients with more advanced stages of endometriosis.
  • Their effects often only last as long as they are taken – after stopping the treatment the pain usually returns to as it was before as the endometriosis regenerates.
  • They further reduce fertility.
  • They are associated with many side effects which mean that they should not be taken on a long term basis ie. more than 6 months (except for combined oral contraceptives and mirena coils) and therefore they provide only temporary pain relief and not a long term solution.

Pain killers such as the non steroidal anti-inflammatory drugs (NSAIDs), ibuprofen and naxopren may be used in the symptomatic management of endometriosis however are generally not very effective.

Medications that aim to manipulate hormone levels or function within the body are also used in the treatment of endometriosis. The three principle hormones whose levels are manipulated are the sex hormones – oestrogen, progesterone and androgens (eg. testosterone). Increasing the levels of progesterone and oestrogen mimics pregnancy (‘psudeopregnancy’). Conversely, decreasing levels of progesterone, oestrogen and increasing testosterone mimics menopause (‘pseudomenopause’). By manipulating the levels of these sex hormones, it is thought that the morphology, function and behavior (eg. prevention of endometrial lesion bleeding) of the endometrial lesions and surrounding tissues can be manipulated, thereby reducing pain. However, these agents are all associated with a number of side effects which limits their long term use:

Medical Agent Mechanism of action Common Side Effects
Combined oral contraceptives Mimics oestrogen and progesterone (pseudopregnancy) Breakthrough bleeding and spotting
Progestin (high dose) Mimics progesterone (pseudopregnancy) Breakthrough bleeding, spotting, fluid retention, weight gain, breast tenderness, mood changes, depression, fatigue
Danazol Mimics testosterone (a male hormone) and reduces production of oestrogen in the body (pseudomenopause) Acne, excessive hair growth and weight gain. On prolonged usage: liver damage and irreversible deepening of the voice.
GnRH agonists Influence the function of the pituitary gland (which is near the brain). Ultimately, this leads to a reduction in both oestrogen and progesterone (pseudomenopause) Hot flashes, mood changes, vaginal dryness, adverse lipid (eg. cholesterol) profile changes and a reduction in bone density

An intrauterine hormone coil (Mirena) may also be used in the symptomatic treatment of endometriosis. This hormone coil slowly releases a progesterone analogue, thereby inducing a state of pseudopregnancy in the same way as oral contraceptives and progestin. As the progesterone is released at a slow rate, it is associated with less side effects than progestins, however side effects such as breakthrough bleeding, acne, headache and breast tenderness may still occur.

Medical treatments (including the coil) of endometriosis are not effective in all patients and pain reduction may only be minimal. In particular, medical treatments are only effective in those with minimal endometriosis (stage I); they are ineffective in more advanced stages of the disease (stages II-IV) as medical treatment is unable to treat deep endometriosis scars, endometriotic cysts and adhesions.

Since all these agents manipulate the levels of oestrogen and progesterone whose normal levels are essential for the normal functioning of the uterus, fallopian tubes and ovaries, their use reduces fertility further. Although this further reduction in fertility is reversed when agent administration is ceased, studies have found medical treatments to cause no increase in fertility after they are ceased.

Thus on the whole, medical treatment is merely suppressive and does not pose the prospect of a long term treatment or indeed ‘cure’. Surgical treatment is the most effective means by which endometriosis can be treated and the only means by which endometriosis can be potentially ‘cured’. For more information on surgical treatment, please view the Surgical Treatment of Endometriosis page.