Lecture 19: Dermatologic Pharmacology (Exam 2) Flashcards
Cream vs Ointment
What is the difference between ingredients, absorption, and use?
C: half oil/half water w/emulsifier (lotion is less viscous)
- spreads easily, well absorbed, washes off w/water
- better for oozing or “wet” skin
O: 20% water/80% oil
- feel greasy and are occlusive (stay on skin surface)
- best for DRY skin; less likely to cause allergic rxns
What is the single most important measure to reduce transmission of microorganisms to other areas of the body or patients?
How long should you do it for and what should be used with it?
HAND HYGIENE
- should wash 15-30 seconds using plain soap
- frequent handwashing can cause skin damage and irritation
What is Alcohol-based hand disinfection and what is it good against vs not good against?
- easier and faster method than soap and water
- good against Gram (+), Gram (-), and viral pathogens but NOT good against C. difficile (use soap and water)
What is the function of emollients, humectants, and horny substance (Keratin) softeners in Moisturizers?
E: form oily layer on top of skin that traps water in skin
- lanolin, petrolatum
H: draw water into the outer layer of skin
- glycerin, lecithin
K: loosens bond between top skin layer cells (dead skin loss), helps retain water, and gives softer feel
- urea, allantoin
What kind of moisturizer would you want for:
Normal Skin Dry Skin Oily Skin Sensitive Skin Mature Skin
N: water based (light and non-greasy)
D: heavy and oil-based (antioxidants: skin hydration)
O: water-based (noncomedogenic - limits acne outbreak)
S: soothing ingredients (aloe) to minimize skin irritation
M: oil-based (petrolatum) to hydrate skin plus antioxidants (prevent wrinkles)
What wavelengths are UVB and UVA radiation seen it and what damage do they cause?
What are the 3 chemical compounds that absorb light in the UVB/UVA ranges? (P, B, D)
UVB: 280-320 –> erythema, skin aging, carcinogenesis
- PABA active in UVB
- benzophenones wider but less effective
UVA: 320-400 –> skin aging and cancer
- dibenzoylmethanes
How are glutaraldehydes, quaternary amines, halogens, and peroxygens used as antiseptic and disinfectants?
G: causes cross-linking of proteins in cell envelope
QA: causes generalized membrane damage to phospholipid bilayer
H: oxidation of thiol groups
P: hydrogen peroxide = free hydroxyl radical generation
What is Chlorhexidines role in antiseptic and disinfectants?
- broad spectrum antimicrobial agent widely used in homes/hospitals due to general EFFICACY on SKIN (including mucosa) and its LOW IRRITABILITY
What are the top 5 most resistant microorganisms to antiseptics and disinfectants?
Prions, Coccidida (cryptosporidium), spores, mycobacteria, and cysts
When should antiseptic and antibiotic wash solutions be used?
Antiseptic: generally not necessary due to minimal action against bacteria and can potentially impeded wound healing
Antibiotics: reserved for wounds that appear clinically infected (no evidence for prophylaxis or non-infected wound use)
What is Wound Debridement and what is the difference between:
Low Pressure Irrigation w/normal saline
Surgical Debridement
Enzymatic Debridement
Biologic Debridement
- removal of dead tissue and debris that promotes wound healing (conserves local resources)
LPI: should be routine, flushes bacteria/removes dead
SD: removing large areas of necrotic/infected tissue
ED: mixed results, promote endothelial/keratinocyte migration for angiogenesis
BD: maggot therapy (negative perception) –> eat dead tissue but leave living, but pressure ulcer healing time not consistently reduced
What is Becaplermin and what is it used for? What is a major warning against its use?
- platelet derived growth factor that promotes cell proliferation/angiogenesis (epidermal GFs do not significantly improve epithelialization)
- ONLY agent approved for Chronic Diabetes Foot Ulcers
- black box warning for MALIGNANCY (use of > 3 tubes = 4x inc. risk of malignancy)
How should wounds be dressed and what items should be used for:
Debridement Stage
Granulation Stage
Epithelialization Stage
- keep wounds moist and NOT exposed to air (occluded wounds heal 40% faster with less scarring)
DS: use hydrogels
GS: foam, low-adherence dressings
ES: hydrocolloid and low-adherence dressings
Topical Antibacterial Agents
What are Bacitracin, Neomycin, and Polymixin B used for and how do they act?
B: inhibits bacterial wall synth
- active against Gram (+), anaerobic cocci and bacilli
- poorly absorbed, causes allergic contact dermatitis
N: inhibits ribosomal subunit 30S (inhibits protein)
- active against Gram (-)
- poorly absorbed, causes allergic contact dermatitis
PB: damages bacterial cytoplasmic membrane
- active against Gram (-)
- rarely causes allergic reaction
Topical Imidazole Antifungals
How do they work and what is the use of Miconazole, Clotrimazole, Efinaconazole, and Ketoconazole?
- block Ergosterol synthesis
Miconazole: cream/lotion; vulvovaginal candidiasis
Clotrimazole: cream/lotion: vulvovaginal candidiasis
Efinaconazole: onychomycosis treatment
Ketoconazole:
- cream - dermatophytosis/candidiasis
- shampoo - seborrheic dermatitis
Topical Antifungals
What are Circlopirox, Terbinafine, and Tolnaftate used for and how do they work?
C: prescription broad-spectrum, blocks macro synthesis
- use for dermatophytes, Candida, Malassezia
Ter: inhibits squalene epoxidase (ergosterol synth)
- use for dermatophytes but NOT yeast
- cream can cause local irritation (NO mucus memb)
Tol: synthetic; distorts hyphae and stunts growth
- use for dermatophyte/Malassezia, NOT Candida