THERAPY

Agonists stop endometriosis agony

- Amanda Hunt-

Gonadotrophin-releasing hormone (GnRH) agonists are efficacious in the treatment of endometriosis, says a US expert on this 'enigmatic condition' .

Dr David Adamson, a professor at Stanford University Medical School, California, and Director of the Fertility and Reproductive Health Institute of Northern California, spoke during a lecture tour in Auckland, New Zealand. He pointed out that endometriosis is a debilitating condition that is estimated to affect 7% of women in the reproductive years; this comprises 5 million women in the US alone.

The main symptom of endometriosis is pelvic pain, which can be very severe. Endometriosis is also a significant cause of infertility, being present in 25-30% of infertile women.

No magic pill While there is no 'magic pill' for endometriosis,

Dr Adamson says that treatment has improved in recent years with the advent of the GnRH agonists. The vast majority of his patients have 'very good' pain relief with GnRH agonists, he continues, and the drugs are his first choice of nonsurgical treatment for endometriosis, because of their sustained efficacy.

Although these agonists can only be used in the short term because of associated bone loss, the benefits of their use extend far beyond the time of treatment. Dr Adamson recommends a treatment period of 6 months, but in his experience benefits in pain relief last from at least I to several years. This is thought to be because GnRH agonists reduce the size of endometriotic growths.

Bone loss problems limit use The major problem with the agonists is that the

hypo-estrogenic state responsible for their therapeutic benefit also causes bone loss. Dr Adamson estimates bone loss during a 6-month treatment course to be in the order of 5-8%. Bone regrowth occurs once the drug is discontinued, however, and bone density is normal 12-18 months later.

Dr Adamson considers the efficacy of the GnRH agonists in endometriosis equal to that of the testosterone derivative, danazol. The agonists have the additional benefit of not affecting liver enzyme and lipid levels, and lack the androgenic adverse effects of danazol (weight gain. acne. oily skin and deep voice).

Many other indications Dr Adamson also recommends the use of GnRH

agonists prior to surgical procedures such as hysterectomy for large fibroids. In cases where patients are anaemic because of heavy menstruation, a 3-month course of treatment with a GnRH agonist induces temporary amenorrhoea and enables an increase in haematocrit, improving the

ISSN 0156-2703l9211114-00171$1.00<C Adls International Ltd

patient's fitness for surgery. Additionally, the agonist can shrink the fibroid growth and thus reduce the extent of surgery required.

Other indications for the GnRH agonists include: • precocious puberty • induction of ovulation • downregulation prior to in vitro fertilisation • hirsutism • premenstrual syndrome.

Studies in the latter 2 indications are currently underway. However, at this stage, only short-term treatment is feasible because of the risk of bone loss.

Adjusting hormone balances In the future, Dr Adamson hopes that fine-tuned

'addback' regimens will allow longer term use of GnRH agonists, in conjunction with low-dose estrogens or progesterones to counteract the osteoporotic effects of the agonists.

While no ideal regimen is yet available, Dr Adamson is hopeful that a combination of progesterone and sodium etidronate [etidronic acid] will enable long-term treatment of conditions such as endometriosis and premenstrual syndrome. Cost benefit studies will need to be performed, as the agonists are potent drugs which cost' a lot of money'.

~ Editorial comment: GnRH agonisfs currentl.>' availahle include huserelin, goserelin, leuporelin and na/are/in.

INPHARMA® 14 Nov 1992

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