Topical medications

Photo of an ointment being applied to hands (PantherMedia / Axel Bückert)

Applying medication to the skin or mucous membranes allows it to enter the body from there. Medication applied in this way is known as topical medication. It can also be used to treat pain or other problems in specific parts of the body.

Topical medication can also be used to nourish the skin and protect it from harm. Some topical medications are used for local treatment, and some are meant to affect the whole body after being absorbed through the skin.

Pastes, ointments and oils

Ointments are mixtures of various fats that can be easily spread. They are made of fat, oil or wax or a combination of these. Common examples are fatty antiseptic ointments and healing ointments.

Oils are made of fat that is liquid at room temperature. They are used as additives for oil baths, as massage oils, or as essential oils such as peppermint oil.

Pastes are special ointments that contain fat as well as a large amount of powder additives. This makes them very thick, and it is difficult to rub them in. One example is zinc paste.

Creams, lotions, and foams

Creams are mixtures of fat and water that can be easily spread. Because fat and water normally won't readily mix, an emulsifying agent is added to combine these two ingredients and keep them stable. The result is also called emulsion. More liquid emulsions on a water basis are called lotions or milk. If air is dispersed in an emulsion, it becomes a topical foam.

Emulsions of water and oil are differentiated by their main ingredient into oil-in-water emulsions (O/W emulsion) and water-in-oil emulsion (W/O emulsion).

O/W emulsions contain more water. Examples include light creams that are easily absorbed and cool and moisturize the skin.

In contrast, W/O emulsions contain more fat than water. They create a protective layer and store moisture in the skin. They are used for richer creams and creams specifically for dry skin as in eczema.

Gels, tinctures and powders

Gels are a special type of water-based cream. They are made primarily of thickeners like starch that can bind a lot of water and the active ingredients dissolved in it.

Gels contain no fat, can easily be spread on the skin and can have various active ingredients in them. There are, for example, gels for relieving pain or anti-itching agents. Gels build a film on the skin and have a cooling effect caused by water evaporating on the skin.

Powders are sprinkled on the skin and stick there. In addition to their solid active ingredient, they can also contain carrier substances (such as talc). Powders have a drying effect and form a film that protects the skin. There are, for example, powders for the treatment of itching or fungal infections.

Tinctures are topical medications in liquid form. They are made by dissolving or diluting dried extracts, often of plant material. Alcohol is commonly used as a solvent. One well-known example is tincture of iodine, which is used for disinfecting wounds.

Shake lotions are skin care products made of a mixture of liquids and solids. Solids make up at least 50% which is why they can be viewed as a kind of "liquid powder." They contain very little to no fat. Two application examples are chickenpox and shingles, where a white shake lotion with zinc is used to dry out the skin blisters. Because the powder and liquid will separate over time, you have to shake these lotions into suspension before use.

Sprays and patches

Some drugs can be applied to the skin or mucous membranes as a spray. There are sprays for treating wounds, for disinfection or for reducing swelling in the nasal mucous membranes, for example.

Some medications that are meant to enter the body over a particular period of time can be applied with the help of a patch. A patch can release a medicine for a specific amount of time. As well as medicinal patches, there are also hormonal and nicotine patches.

This type of application has several advantages: The medication is absorbed very evenly, and does not cause any trouble for the gastrointestinal tract. And patches are convenient to use. These types of patches are also called “transdermal therapeutic systems” (TTS). It is important to take off the old patch before applying the new one, and to be careful not to always put it in the same place.