Integumentary System
Lesson 5: Dermatological Drugs
5-5
5-5. TYPES OF TOPICAL FORMULATIONS
A topical formulation is medicine that is applied directly to the skin as opposed to a capsule that is swallowed or medication inserted directly into a vein. There are a number of topical medications: wet preparations, powders, shake lotions, creams, pastes, ointments, hydrocarbons, gels, and adherent dressings. The type selected depends on several factors: the characteristics of the skin problem; the general character of the patient's skin; previous medication; and drug allergies.
a. Wet Preparations.
(1) Baths, soaks, and wet dressings are referred to as wet preparations. The preparation selected depends on the location and size of the affected skin area. Each wet preparation can cleanse the skin and reduce itching.
(2) Wet dressings are wet compresses applied to skin areas. Wet dressings are used mainly when skin lesions are highly inflamed or are draining. When medicine is applied and then covered by a wet dressing, the lesion stays open and can drain freely. Wet dressings are used in treating oozing dermatitis (skin problems) or swollen, infected dermatitis (furunclitis, cellulitis). These dressings relieve the inflammation, burning, itching, and have a cooling effect on the skin. Wet dressings are suitable for even the most acute skin lesions.
(3) These solutions are commonly used in wet dressings to promote healing and produce a soothing effect:
(a) Normal saline solution--nonmedicated and hypoallergenic; used when treatment calls for drainage and heat.
(b) Burrow's solution--aluminum acetate solution; similar to boric acid but is less effective in preventing the growth of bacteria. It is more drying.
(c) Milk and lime water--used around the eyes or genitalia as a soothing, cold solution.
(d) Hypertonic magnesium sulfate solution--provides drainage and reduces swelling and inflammation.
(e) Boric acid solution--used for inflamed, superficial infections.
(f) Silver nitrate solution--an astringent (causes tissues to contract and reduces drainage) that kills bacteria and fungi.
(g) Vleminchx's solution--saturated lime solution which kills bacteria and fungi.
(4) Soothing baths are used when the skin problem is over a large area of the body and most frequently when the skin lesions itch; for example, chicken pox lesions. In addition to reducing itching, baths can be used for weeping, oozing erythematous (red) eruptions. Keep the water at a comfortable temperature, and avoid hot baths. A hot bath can burn the patient. Also, be sure to use a bath mat because medications used in the water may make the bathtub slippery. Substances used in baths include oatmeal, aveeno, and cornstarch. Such substances have a cooling and drying effect on the skin and reduce the itching.
b. Powders. Powders are used when there is a need to increase evaporation (dry the affected area), reduce friction, provide antipruritic (relieve itching) and cooling sensations, absorbent, drying effect, or for fungal infections. Zinc oxide, talc (magnesium silicate), and titanium dioxide are powders which reduce friction and absorb moisture. Powder should not be used if the patient is hypersensitive or has oozing skin surface. An oozing skin surface causes powder to cake and actually promotes bacterial growth. There are some side effects to powders. The starch in the powder can cause overgrowth albicans (a yeast-like fungi most commonly responsible for infections such as thrush and vaginitis). Talc, a useful protection for skin irritations such as prickly heat and diaper rash, should not be applied to healing wounds; the talc can cause severe granulomatous reactions (the formation of small, rounded, fleshy masses on the surface of a healing wound).
c. Shake Lotions. A solution or suspension of medication is the definition of a shake lotion. The name, shake lotion, comes from the fact that the solution is fine powders suspended in liquid and must be shaken thoroughly before use. The advantages of using medicated shake lotions are that they are easy to apply and stick well to the skin area. A disadvantage of shake lotions is that they may dry too much when applied to acute lesions. Also, shake lotions do not penetrate thickened chronic lesions as well as creams or ointments. A common shake lotion is calamine lotion. Once pink because of iron salts present as impurities, calamine lotion is now prepared from zinc oxide and prepared calamine.
d. Creams. Creams are an intermediate preparation between wet dressings that dry the skin lesion and ointments that keep lesions moist. Creams are semisolid, have a high percentage of water, are water-
washable and don't leave the greasy residue after use that ointments leave. Additionally, creams absorb fluids from the skin. Cream spreads so easily on the skin that any medication dissolved in the cream comes in good contact with the skin.
e. Paste. Paste is a suspension of twenty percent to fifty percent powder in a greasy ointment base. Thicker and drier than ointments, paste does not penetrate as well as ointments but does not seal the wound as completely as ointments. Do not use paste on weeping lesions or hairy areas.
f. Ointments. An ointment is a preparation in which a drug is suspended or dissolved in a grease or oil base. Substances which may be used as a base include petrolatum, liquid petrolatum (mineral oil), olive oil, lanolin, and other animal fats. Ointments penetrate thickened lesions and act as an emollient (that is, soften skin and overlying crusts or scales). Ointments do not, however, permit drainage or evaporation and by trapping moisture may cause tissue to be softened from moisture. Do not apply ointment to hairy areas of the body because the ointment may penetrate to the base of a hair follicle causing folliculitis.
g. Other Types of Medication. Medication for skin problems also comes in the form of soaps, shampoos, and sprays. Each of these is used to treat particular skin problems.
(1) Soaps and soap substitutes. When regular soaps cause the skin to become excessively dry and irritated, a neutral soap called Oilatum can be used. People with oily skin can use Fostex® cake, Lava® soap, and Acne-Aid® detergent soap. Two other medicated soaps are Gamophen® and Mycoderm®. If soap proves too irritating to a person's skin, try soap substitutes such as Lowilacake®, Acidolate®, pHisoderm®, or pHisoHex®.
(2) Shampoos. These medicated shampoos are used to treat seborrheic dermatitis, a common skin disorder which can range from mild to severe. The skin lesions are reddish plaques with yellow, greasy scales and usually appear on the scalp, the middle of the face, the middle of the body, the eyebrows, and the ears. Shampoos used to treat this skin problem include Capsebon®, Sebulex®, Betadine®, Domerine®, Ar-Ex Tar®, Fostex Cream®, and Alvinine®. If the skin condition is caused by head lice and their eggs, use Kwell® shampoo. To use these shampoos most effectively, wet the hair with warm water and apply the shampoo as you would any shampoo. Allow the lather to remain on the scalp for at least five minutes. Wash the shampoo out of the hair; no special rinse or cleansing agent is necessary. Although medicated, these shampoos have a pleasant odor and leave the hair feeling soft. These shampoos are normally used several times a week as recommended by the doctor. Kwell® need only be used once for treatment of lice.
(3) Sprays (aerosols). Sprays are particularly good for moist skin lesions. Medication applied directly to the affected area could cause additional irritation from rubbing and more contamination and infection. Sprays are usually applied several times a day. Shake the container before using; then, with the can upright, spray the affected area from a distance of 3 to 6 inches. A spray of 2 to 3 seconds at a time is usually sufficient. To spray longer is a waste of medication. Sprays that contain corticosteroid and antibiotic-steroid medication include Diloderm®, Neo-Diloderm®, Meti-Derm® with neomycin, and Tarcortin®. A spray over which a bandage can be put is Betadine®, which is nonstinging and nonstaining. Anesthetic sprays include Americaine® and Tronothane®. A common antifungal spray is Desenex®. Two foams that come in aerosol containers are Aristoderm® (a steroid spray) and Neo-Aristoderm® (a steroid preparation). Apply foams by holding the can upside down next to the skin.
(4) Hydrocarbons. Medications containing hydrocarbons (a compound of hydrogen and carbon) are protective and greasy. Hydrocarbons are a stable medium for lipid soluble antibiotics. White petrolatum (Vaseline®) and mineral oil are examples of this type of medication. These skin medications have a soothing effect on chapped, irritated skin. The medication holds water in the skin and acts as a barrier for all outside irritants--air, wind, and dirt. Podophyllum is an example of a medication used in combination with hydrocarbons.
(5) Gels. Like hydrocarbon medications, gels act as a barrier against any outside irritant like dirt or wind. A gel can change from a solid to a liquid and from a liquid to a solid, having the advantages of both.
(6) Adherent dressings. These dressings are coated with a substance that helps the affected skin area dry. Adherent dressings also prevent irritation of the adjoining skin tissues. Substances that can be used on adherent dressings are tincture of benzoin and flexible collodion.
