Progestogen-only contraceptives are available as tablets (levonorgestrel or norethisterone); injection — Depot (medroxyprogesterone acetate); and progestogen-releasing intrauterine contraceptive devices (levonorgestrel). The progestogens suppress the LH pulsatile release and inhibit ovulation. Progestogens also thicken the cervical mucus, making sperm transport difficult, and thin the endometrium so that implantation cannot occur. These Pills, often referred to as Mini Pills, are often used when women are breastfeeding, or when there is a prior history of thromboembolism. The progestogen-releasing IUD is a useful option for women with menorrhagia who also need contraception.
Injected progestogens are indicated when there are problems with poor compliance or when gastrointestinal problems interfere with absorption of oral preparations. Depo-Provera is an injectable form of medroxyprogesterone acetate and is used as a long-term contraceptive. It can cause a number of side-effects, including prolonged episodes of menstrual irregularity and heavy bleeding, or alternatively amenorrhoea can persist for many months after cessation of the drug. A recent study indicating this type of contraceptive has adverse effects on bone density raises questions about its suitability for young women requiring contraception.
Danazol is another progestogen which can cause pronounced androgenic effects such as male-pattern hair growth, deepening of the voice, weight gain, acne, and changes to the sexual organs such as atrophy of breast tissue, and hypertrophy of the clitoris. Severe and life-threatening strokes or thromboembolism, and increased intracranial pressure have also been reported with the use of danazol. Long-term use may cause serious toxicity including jaundice and hepatitis. Some women find it also causes severe mood changes and symptoms like premenstrual syndrome.
This drug needs to be carefully prescribed after due consideration of the risks and benefits for each woman. For endometriosis, danazol is prescribed in high doses (between 200-800 mg per day) to stop ovulation, suppress the period and cause the endometrium (both inside and outside the uterus) to shrink. Spotting can be a problem and is usually managed with a change in dose. Danazol improves period pain and other pelvic pain, seems to have beneficial effects on the immune abnormalities of endometriosis, is better than other progestogens in improving fertility, and does not have an adverse effect on bone density.
This progestogen can also be used on a daily basis to suppress ovulation for the treatment of breast pain and to improve lethargy, anxiety and increased appetite associated with premenstrual syndrome (PMS). For these conditions, it is used at doses of around 200 mg which cause less side-effects and tend not to stop the period. This is generally an unpopular treatment because the side-effects are unacceptable; however, some women with premenstrual syndrome reported a reduction in breast pain, fatigue, food cravings and anxiety. Doses of around 200 mg for two to four months have been trialled for benign breast disorders and have led to a reduction in pain and lumpiness in 70 per cent of women. Recurrence of symptoms was observed in between 6-10 per cent of another group of women who were followed for four years. There has been some success using danazol during the second half of the cycle only for premenstrual breast pain. This regime does not stop ovulation and the exact mechanism involved is unknown.
Danazol is sometimes used when abnormal bleeding has not responded to other treatments, but usually only when surgery is undesirable or not indicated, or when there are long waiting lists for hysterectomy. The dose is between 200-400 mg daily.
Side-effects from danazol are difficult to control, especially at the higher doses required for the treatment of endometriosis. However, trying the supplements suggested for the Pill can sometimes alleviate unpleasant symptoms.