Help physicians choose between different TOPICAL dosage forms

For DRY skin, consider an ointment, their emollient effects help rehydrate skin. But caution that they may be sticky and stain clothes....

There are reasons to choose one topical dosage form over another. Tailor your choice based on skin type, the affected area, patient preference, and cost. And use these general rules of thumb...

Creams work well for most areas, since they spread easily, vanish when rubbed in, and usually aren't greasy. For DRY skin, consider an ointment, their emollient effects help rehydrate skin. But caution that they may be sticky and stain clothes. For OILY skin, choose a gel, lotion, or foam, partly because they dry quickly and aren't greasy. Plus the alcohol in some products can have a drying effect on the skin. For SWEATY skin, keep in mind that powders can help absorb perspiration in areas such as on the feet or in skin folds. For the SCALP or HAIRY skin, try a gel, lotion, or foam. These spread easily and aren't greasy.

Be aware the dosage form can impact drug absorption, especially with corticosteroids. For example, betamethasone 0.05% (Diprosone) augmented ointment is VERY HIGH potency, the augmented cream is HIGH potency, and the non-augmented lotion is MEDIUM potency. Try to stick with similar dosage forms if you need to substitute a non-formulary topical product with a formulary option.

Table (1). Guide to Selecting Topical Dosage Forms
Dosage Form	Non-greasy	Easily Spread	Quick-Drying	Best for Skin Type	Comments
Creams	✓ (Usually non-greasy, but can be moderately greasy)	✓		Most; hairy and non-hairy Dry or sensitive Exudative	Often preferred by patients Moistening, emollient properties Less hydrating than ointments Provides no occlusion Minimal residue
Ointments				Non-hairy Very dry, thickened, scaly	Not generally preferred by patients Occlusive, protective barrier Messy, greasy: can stain clothing, etc Hard to wash off Emollient effects can rehydrate skin
Pastes				Non-hairy Very dry, thickened, scaly	Thickest formulation Messy, greasy: can stain clothing, etc Hard to wash off Not well absorbed, provides a protective barrier Emollient effects can rehydrate skin Starch-containing formulations can absorb secretions
Lotions	✓	✓	✓	Hairy, scalp Areas prone to chafing (e.g., groin, armpits, etc) Face Oily	Patients may like light feel Drying effect Cooling sensation, as it evaporates quickly Doesn’t remain on the skin as well as creams and ointments Good for large areas Can use with make-up
Foams	✓	✓	✓	Hairy, scalp Inflamed, sensitive Face Oily	Improved patient adherence over traditional creams and ointments Cooling sensation Easy, quick application Good skin absorption Minimal residue May be good if covering a large surface area Can cause burning, stinging, pruritus less with alcohol-free foams Fast penetration, high rate of total absorption Can use with make-up
Gels	✓	✓	✓	Face Hairy, scalp Oily	Often preferred by patients Cooling sensation Easy to wash off, including with perspiration Alcohol-containing formulations can dry skin Can use with make-up Liquefy on contact with skin, forming a non-occlusive film No emollient or skin protective properties Fast release of the medication Can cause burning, itching, dryness, irritation, peeling, redness Some contain glycerin (promotes moisture retention) or dimethicone (emollient) to reduce irritation and increase hydration
Sprays	✓	✓	✓	Most	Easy to use on large areas Can cause erythema, scaling, dryness, stinging, burning
Powders	✓		✓	Exudative Areas prone to chafing (e.g., groin, armpits, etc)	May be used to absorb secretions
Liquids (suspensions, solutions, etc)	✓	✓		Hairy	Messy No emollient, occlusion, or skin protective properties
These information from references... Kurian A, Barankin B. Delivery vehicle advances in dermatology. December 2015. Skin Therapy Letter. http://www.skintherapyletter.com/fp/2011/7.2/2.html. Rosen J, Landriscina A, Friedman AJ. Principles and approaches for optimizing therapy with unique topical vehicles. J Drugs Dermatol 2014;13:1431-5. Weiss SC. Conventional topical delivery systems. Dermatol Ther 2011;24:471-6.

IMPORTANT NOTE..

Estimating Dispensing and Application Amounts

Try using the Rule of Hand to help you calculate accurate amounts. One gram of cream will cover about four flat adult hands (wrist to fingertips with fingers together, i.e., four handprints). For example, a cream applied twice daily to an adult’s left forearm for 14 days would require about 14 g of cream. An adult hand covers roughly half of an adult’s forearm, so two flat hands = 0.5 g would cover the entire forearm one time. Therefore, you would need 0.5 g twice daily = 1 g per day for 14 days = 14 g total. Match this amount to the closest tube size of the cream being dispensed (e.g., 15 g, 20 g, etc).
You can use the Fingertip Unit method to instruct patients on how much cream they should use per application and to help you determine the total amount to dispense. One fingertip unit is the amount of a topical preparation that can be squeezed out of a standard tube along an adult fingertip (fingertip to the crease of the first joint). One unit is enough to cover both sides of an adult hand with the fingers together. Use these estimates to figure out how much cream your patient should use per application: 2 units cover one adult foot; 2.5 units cover an adult face and neck; 3 units cover one adult arm (shoulder to wrist); 6 units cover one adult leg; 7 units cover an adult trunk (either front or back). One fingertip unit is about 0.5 g of cream... Four flat adult hands = two fingertip units = 1 g of cream.

References

Weiss SC. Conventional topical delivery systems. Dermatol Ther. 2011 Sep-Oct;24(5):471-6.
Rosen J, Landriscina A, Friedman AJ. Principles and approaches for optimizing therapy with unique topical vehicles. J Drugs Dermatol. 2014 Dec;13(12):1431-5.
Ference JD, Last AR. Choosing topical corticosteroids. Am Fam Physician. 2009 Jan 15;79(2):135-40.