Topical medications

Ointments are mixtures of various fats that can be easily spread. They are made of fat, oil or wax, or a combination of these. A common example is diaper (nappy) rash ointments that have a soothing and healing effect.

Oils are made of fats that are 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-like substances. This makes them very thick, and it is difficult to rub them in. One example is zinc paste.

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 resulting mixture is called an emulsion. Runnier water-based emulsions are called lotions or milk. If tiny bubbles of air are formed in an emulsion, it becomes a topical foam.

Depending on their main ingredient, emulsions of water and oil are described as either oil-in-water emulsions (O/W emulsion) or water-in-oil emulsion (W/O emulsion).

O/W emulsions contain more water. Examples include light creams that are easily absorbed by the skin and have a cooling and moisturizing effect.

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, for instance in eczema.

Gels are a special type of water-based cream. They mainly consist of thickeners like starch that can bind a lot of water and the drugs dissolved in it. Gels contain no fat, can easily be spread on the skin and can have various drugs in them. Examples include gels for relieving pain or itching. 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. As well as having a solid active ingredient, they sometimes 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 of plants or other substances. Alcohol is commonly used as a solvent.

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

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 doesn't cause any trouble in the stomach or bowel. And patches are convenient to use. These types of patches are also called "transdermal patches" or “transdermal therapeutic systems” (TTS). It is important to take off the old patch before applying a new one, and to be careful not to always put it in the same place.