Archive for Май 8th, 2009
HORMONAL REPLACEMENT THERAPY: TRANSDERMAL HRT
The patch is a circular piece of ‘plaster’ that you stick on to a fleshy part of you. In the centre is a reservoir of oestrogen that is carried through the surface of your skin in a base of alcohol.
Probably the biggest advantage the patch has over tablets is that, because the oestrogen is absorbed through the skin (doctors call this ‘transdermal’ HRT, meaning ‘across the skin’) and does not have to go through the liver and the rest of the digestive system, it is taken in a much lower dose and has fewer side-effects. It is easy to use, and easy to stop if you find it doesn’t agree with you. Also, the oestrogen is absorbed at a slow, constant rate, whereas if you use oral HRT you are taking the hormone in one dose all at once, which can increase the likelihood of side-effects, particularly in the digestive system.
The patch is simple to use: you just stick it on to a well-padded area of clean, dry skin, such as the buttocks, abdomen or upper thighs, and change to a new patch every 3-4 days, by which time all the alcohol and oestrogen will have been absorbed. You must not stick it on to the breasts. The main drawback with this form of HRT is that about one-third of women find they develop red and itchy skin at the site of the patch, and in a very small percentage this becomes so severe that they have to give up. This is caused by the alcohol contained in the patch and there are two possible solutions. One is to move the patch to a new area of skin every day (but still only having a new patch every 3-4 days), and sticking it down with a piece of elastoplast across it. The other is to wave the patch about in the air for a few seconds before applying it so that some of the alcohol evaporates. Don’t do this for too long, however, as it is the alcohol that transports the oestrogen through the skin; no alcohol means no oestrogen. More of the oestrogen is absorbed through the abdomen than through the buttocks or upper thigh, but the buttocks usually give the least skin irritation. (Before long, a new HRT patch will be available without an alcohol base; this should eliminate the problem of skin irritation.)
The skin reacts more to the patch in a hot, humid climate, so some women find it a problem if they go to a hot country on holiday. Leaving the patch off when you lie in the sun is one solution, or possibly changing to tablet HRT while you are away, but this might cause undesirable side-effects. If the patch comes off after swimming or a bath or shower, just stick the same patch back on again with some elastoplast.
The patch comes in three different strengths: 25, 50 and 100 micrograms of a form of oestrogen called oestradiol. If you find it is not having the desired effect, don’t be tempted to change to a new patch more frequently as this will not increase the amount of oestrogen you absorb. If you are not happy with its effect, ask your doctor about changing to a patch with a higher or lower dose.
The patch is generally well tolerated, and many prefer it to tablets and are less likely to give up. As before, if you haven’t had a hysterectomy, you will have to take progestogen for 10-12 days a month. Until fairly recently, progestogen was only available in tablet form, but there is now a combined oestrogen and progestogen patch called Estracombi, manufactured by Giba-Geigy. For the first two weeks of the cycle, oestrogen-only patches are worn for 3-4 days each; for the following two weeks, the double oestrogen and progestogen patches are worn for 3—4 days each. Because each double patch contains both hormones, it is not possible to use only the oestrogen patch for this phase of the cycle and to leave the progestogen patch in its box! The manufacturers report that symptoms similar to premenstrual syndrome may be a problem for up to three months, but these should diminish after that time.
The patch method of taking HRT has die same beneficial effects as oral HRT on hot flushes, night sweats, disturbed sleep, changing moods and vaginal dryness. Research suggests that, except at the lowest doses, it also preserves bone in 85-95 per cent of women, but because it is a comparatively new form of HRT it is not yet known for certain the extent to which it provides the same protection against arterial disease. Like oral HRT, the patch can cause breast tenderness, spotting, bloating and feelings of nausea, but these are seldom severe.
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