Forms of application of hormone substitution therapy

During the pre- and peri-menopause, over a period of several years, hormone production by the ovaries declines, until it comes to a complete halt with the onset of menopause (the last menstrual period). At this point, estrogen levels in the body are significantly lower, which can lead to a number of disorders associated with this deficiency.

The aim of hormone replacement therapy (HRT) is to supply hormones externally, in order to alleviate the symptoms associated with hormone deficiency. HRT is always tailored to each woman's individual situation. Similarly, HRT requires a careful assessment of risks and benefits. Depending on age, lifestyle, possible illnesses and symptoms, the gynecologist will recommend the treatment best suited to the individual case, with an appropriate dosage and form of administration.

Today, there are various forms of administration. The most suitable type of application depends not only on personal preferences and needs, but above all on the woman's risk profile. If, for example, there is a high risk of thrombosis, a form of application should be chosen that does not increase this risk.

Generally speaking, the motto of HRT is: "Start slowly!" Indeed, HRT generally starts with a low dose of estrogen. Since not only efficacy but also possible side effects depend on dosage, the minimum amount of hormones needed to relieve symptoms is used. ¹

HRT has long been available in oral form. In this case, the hormones reach their destination via the gastrointestinal tract and the liver, where some of them are, however, directly metabolized and broken down. This means that with this form, higher doses have to be administered to ensure that the required amount of active substance reaches the bloodstream.

During transdermal application, the hormones bypass the gastrointestinal tract and liver, passing directly through the skin into the bloodstream. Although the daily dose of hormones is roughly identical to that of oral application (between 0.75 mg and 3.0 mg estradiol), the body ultimately receives smaller quantities of hormones from transdermal application than from hormone tablets. In fact, only a small proportion of the hormones applied to the skin penetrate the body, depending on the preparation, and this can sometimes be of the order of 5%.

Transdermal use can be particularly advantageous for women at increased risk of thrombosis or other cardiovascular diseases. Unlike oral treatment, the risk of thrombosis is not increased by transdermal application. ²

If the problem is mainly local, as in the case of vaginal dryness, HRT can only be applied to the area of the body concerned. In this case, estrogen-containing creams, vaginal tablets or vaginal ovules are appropriate.

In the case of estrogen treatment, all three forms of administration are possible: transdermal, oral or vaginal.

Progestins , on the other hand, are generally administered orally, in the form of capsules or tablets, alone or in combination. ³ These may be bio-identical or of synthetic origin. Taking a progestin is important because it prevents excessive growth of the uterine mucous membrane due to estrogen administration, and helps to rebalance an irregular menstrual cycle. In this way, the uterus remains protected against bleeding and endometrial hyperplasia, the precursor to uterine cancer.

The principle is as follows: the ideal form of application relieves distressing symptoms with the minimum dose of hormones required. Indeed, the treatment must be as easy to apply and as well tolerated as possible. This is also the best condition for regular use.