Principles of Topical Therapy
- The efficacy of a topically applied drug depends on its _____ and _____.
- 5 factors which affect penetration
- inherent potency & ability to penetrate skin
- concentration of medication
- thickness/integrity of stratum corneum
- frequency of application
- occlusiveness of vehicle
- compliance
- ____ are meant to enhance the beneficial effects of the medication.
- ___ may cause local toxicity
- ____ may induce systemic toxicity
- Topical formulations (vehicles)
- vehicle or active ingredients
- topical meds
List the 10 regions of the body from greatest penetration #1 to less penetration #10.
- Mucous membrane
- Scrotum
- Eyelids
- Face
- Chest/back
- Upper arms/legs
- Lower arms/legs
- Dorsa of hands/feet
- Palmar and plantar skin
- Nails
____ maximize the skin penetration of the drug
- Moistening or drying effects have therapeutic benefit
Vehicles
Give an example of occlusion which maximizes efficacy of topical medication?
Application of plastic wrap
How are topical dermatologic treatments grouped?
According to their therapeutic functions:
- Cleansing agents: soaps / solvents
- Absorbent dressings
- Anti-inflammatory: corticosteroids
- Astrigents: drying agents
- Moisturizing: emollients
Topical Therapy Considerations
- Vehicles: ointments, creams, lotions, foams, gels, solutions, sprays
- Class selection: most often used w/ ____
- Appropriate quantitiy for BSA involved: Follow what rule? 1 palm area = __%
- Enhance absorption
- _____: rapidly diminishing response to successive doses of a drug, rendering it less effective
- corticosteroids
- Rule of 9s / 1%
- Tachyphylaxis
Rule of 9s
- 1 palm area = __% of BSA
- 2 palm areas at 2 times a day requires ___ gm for ___
- 1%
- 30gm / 1 month
What does FTU stand for?
- __ FTUs are about the same as __ g of topical steroid.
- 8 adult hands needs, need ___ FTUs for each dose. (2g/dose)
Fingertip Units for corticosteroids
- 2 / 1g
- 4
FTUs (how many adult hands?) / FTU?
- Hand & Fingers (front & back)
- Front of chest + Abdomen
- Back + buttocks
- Face + neck
- Entire arm + hand
- Entire leg + foot
Adult hand / FTU
- hands & fingers: 2 / 1
- chest & abd: 14 / 7
- back & butt: 14 / 7
- Face & neck: 5 / 2.5
- arm & hand: 8 / 4
- leg & foot: 16 / 8
Enhance absorption by covering a topical area.
5 coverings?
- plastic wrap
- cellophane
- waterproof dressing
- cotton socks
- nylon suit
Which vehicle?
- May be mixed w/ active agents; lesions in moist or intertrigenous areas
Powders
Which vehicle?
•Baths and soaks - applied to large areas
•Foams - alcohol- or emollient-based aerosolized preparations; favored in hair-bearing areas
•Solutions - ingredients dissolved in a solvent
•Lotions - water-based emulsions; easily applied to hairy skin; cool and dry acute inflammatory and exudative lesions
•Gels - ingredients suspended in a solvent thickened with polymers; controlled release of topical agents
Liquids
Which vehicle?
•Creams - semi-solid emulsions of oil and water
•Ointments - oil based (eg, petrolatum) with little if any water
Combinations of liquid and oil
4 functions of dressings
- protect open lesions
- facilitate healing
- increase drug absorption
- protect the patient’s clothing
Which dressing?
- most common are gauze dressings
- maximally allow air to reach the wound
- allow the lesion to dry.
Non-occlusive dressings
Which dressing?
- nonocclusive dressings wetted saline solution
- help cleanse and debride thickened or crusted lesions
- applied wet and removed after the solution has evaporated
- materials from the skin adhering to the dried dressing.
Wet-to-dry dressings
Which dressing?
- increase the absorption and effectiveness of topical therapy
- most common are transparent films (plastic household wrap) or flexible, transparent, semi-permeable dressings
- hydrocolloid dressings can be applied with a gauze cover in patients with cutaneous ulceration
Occlusive dressings
