Local therapy
Under local therapy or topical therapy is the application of medical drugs where they therapeutically should act, in contrast to the so-called systemic administration of drugs , for example, as an infusion or tablet.
While local therapy does not play a role in some medical specialties because the organs to be treated are not directly accessible, in other medical fields it is the main form of therapy. Dermatology , ophthalmology and ear, nose and throat medicine are essential here , and it is also used in gynecology .
Local therapy in dermatology
Local therapy is of greatest importance in dermatology . Most of the dermatologically important drugs can be applied directly to the affected areas of the skin . This has several advantages:
- The active ingredients only work where they are needed, while protecting healthy skin.
- Local application can avoid many systemic side effects of the drugs.
- Choosing the right foundation can make a decisive contribution to the success of the treatment. At the same time, choosing the wrong foundation can aggravate the skin disease .
The essential basics in dermatology are arranged in the phase triangle of local therapy.
- Fatty ointments : Pure fatty ointments are used very rarely, as they are not tolerated by patients, especially at higher temperatures . Fatty ointments help dry skin to gain moisture . But they also close the pores of the skin and thus cause heat to build up, so that they can make the situation worse in the event of acute inflammation . They do not absorb much into the skin, so that patients very often have the feeling that they have only just been put on.
- Ointments : Ointments are mixtures of a high proportion of fat with only a small amount of liquid added. Like pure fat, ointments are also mainly applied to dry areas of the skin, absorb a little better, but can also become occluding . In the case of acutely weeping dermatoses, they are contraindicated without further application of moist compresses (“fat-moist principle”) . In connection with the moist compresses they can then be used and have the advantage over the creams that they contain almost no emulsifiers that z. B. are allergic .
- Creams : Creams are mixtures of roughly equal proportions of fat and liquid . So that the two components do not separate again, emulsifiers must therefore be added to them. Creams are more pleasant than ointments for many patients because they are absorbed more quickly. If the skin is very dry, however, they can worsen the skin dryness due to the high water content. In addition, it must be noted here that the emulsifiers can induce many contact allergies .
- Lotion / Milk : Like creams, lotions are mixtures of fat and liquid with an even higher proportion of liquid. As a result, they act z. B. cooling, but can dry out the skin. You put them z. B. in acute inflammatory dermatoses , where you want to take advantage of these effects, z. B. sunburn.
- Liquid : The liquids ( tinctures ) used in dermatology are either aqueous , alcoholic or aromatic . On a watery basis, they are most likely to be used for cooling in acute inflammatory dermatoses (e.g. for preparing poultices or in combination with ointments based on the "fat-damp principle"). Solutions prepared on an alcoholic or aromatic basis are e.g. B. in contrast to aqueous solutions antiseptic , but dry out the skin very quickly due to evaporation. But the drying effects should not be forgotten even when using water.
- Shaking mixture : A suspension of a solid in a liquid solution is called a shaking mixture ( lotio ). No emulsifiers are added here, the solid has to be mixed with the liquid by shaking each time it is used. Application areas are e.g. B. very weeping skin diseases , also with blistering. The combination of liquid and solid ensures a maximum drying and cooling effect. The solid then remains on the skin and is usually a whitish crust .
- Solids : The use of solids in powder form is rather negligible today. Powders can help absorb liquids. However, application is difficult because it is often uneven and the solids alone do not adhere well to the skin.
- Pastes : A mixture of solids and fats is called a paste . Pastes are applied where you e.g. B. wants to achieve a special skin protection , z. B. in the skin folds in the groin , under the chest or between the buttocks . The fat is absorbed by the skin, while the solid is deposited on the skin, preventing folds of the skin from rubbing against each other and worsening the inflammation . As with the shaking mixture, the use of pastes usually leaves whitish crusts . Therefore you should z. B. rather not use on the face.
- Cooling pastes : A mixture of a paste and a liquid is called a cooling paste. It combines the properties of a paste with the cooling effect of a liquid.
In addition to the selection of the right foundation, other effects can be achieved through associations etc.
Occlusion (airtight seal): If you want to intensify the effects of an active ingredient , you can bring about an additional effect by occluding the treated area . The hands , feet and scalp ("head cap") are particularly suitable for occlusion . The main application area for occlusive dressings are rather dry, scaly or with strong horny layer provided dermatoses . Occlusive application of ointments containing urea or salicylic acid on the hands or feet can loosen thickened layers of horny skin in hand and foot eczema . Often one can only achieve that an active ingredient can penetrate the otherwise rather repellent horny layer and exert its effect.
Fat-moist active principle: As already mentioned above, this means the simultaneous use of ointments and aqueous solutions. This form of local therapy is very suitable, for example, in atopic dermatitis . By using ointment, the skin is regained the necessary oil. Moist bandages applied at the same time (e.g. hose bandages on the extremities) cool the skin and have an itch-soothing effect.
In addition to the base and the active ingredient, many topical therapy drugs contain additives such as preservatives, odorants and colorants. However, it is often these additives that trigger allergies in patients . For this reason, ointments, creams, etc. are often produced directly in hospital pharmacies - without additives, but with less shelf life.
Local therapy in other medical specialties
In ophthalmology , eye drops or ointments are used. This is one way of achieving high drug concentrations in a targeted manner in the anterior segment of the eye. The choice of base (ointment or drops) is nowhere near as essential as it is in dermatology . In ear , nose and throat medicine , products for local therapy on the ears , nose and for the oral cavity are available in drop or spray form . Urologists and gynecologists sometimes treat diseases of the external genital organs with local therapeutic agents (e.g. vaginal suppositories ). But here too, as in the oral cavity, many diseases are also treated by dermatologists .
