Lecture 19: Dermatologic Pharmacology (Exam 2) Flashcards Preview

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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?


- 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
- 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


Topical Antifungals

What are nystatin and amphoteracin B used for and how do they work?

N: binds fungal sterols --> alters membrane permeability
- use for cutaneous/mucosal candida infections
- hold in mouth before swallowing (low GI absorption)

AB: binds to fungal sterols --> alters membrane permeability
- use for cutaneous candida infections
- cause yellow-staining of skin (temporary)



What is it, what does it treat, and how can it be given (3)?

- synthetic guanine analog that inhibits Herpes Simplex 1/2 (topical antiviral)

- treats recurrent orolabial HSV infection in immunocompromised

- given as ointment, cream, or buccal tablet


What Pruritus are these topical therapies used for:


T: anogenital pruritus (transient burning/stinging)
- topical calcineurin inhibitor
C: neuropathic itch (transient burning/stinging)
P: face pruritus and that associated with CKD
- local anesthetics


When should low-potency vs high-potency topical steroids be used?

Low-potency --> face, genitals, and skin folds

High-potency --> usually started everywhere else to gain control then titrated downward for maintenance


How does Capsaicin work?

How does Menthol work?

- activates TRPV1 (heat) channels in cutaneous nerve fibers = activation and depletion of neuropeptides, like substance P

- can also induce lasting desensitization of neurons to a variety of stimuli

- substance is derived from Chili Peppers

**use MENTHOL in pts soothed by cooling effects --> activates TRPM8**


What Pruritus are these SYSTEMIC therapies used for:


N - cholestatic and CKD-associated pruritus
- u-opioid receptor antagonist
B - nocturnal and intractable pruritus
- k-opioid receptor agonist/u-opioid antagonist
G - neuropathic Pruritus
- anticonvulsant
A - intractable pruritus (mainly control nausea/vomiting of chemotherapy)
- substance P antagonist


What two substances are used to treat Rosacea? (BO)

brimonidine - alpha2 agonist (topical gel)

oxymetazoline - alpha1/2 agonist (topical cream)


What four substances are used to treat Red Eyes? (NTPO)

naphazoline, tetrahydrozoline, phenyephrine, and oxymetazoline

- all adrenergic receptor agonists


What are four treatments for killing ectoparasites and how do they work? (M/P/I/L)

Malathion - organophosphate cholinesterase inhibitor

Permethrin - blocks membrane repolarization (Na+)

Ivermectin - hyperpolarizes nerve and muscle cells by binding glutamate Cl- channels (GIVEN ORALLY)

Lindane - disrupts GABAergic transmission in insects
- ONLY used after other agents FAIL


What topical retinoid is used to treat acne and what are some side-effects (2) that use can cause?

TRETINOIN (once daily at bedtime)

- causes local skin irritation and should caution in pts with known fish allergies


What 3 topical antimicrobials are used to treat acne (BP/C/E) and what are side-effects that use can cause?

Benzoyl peroxide (skin irritation), Clindamycin (rare pseudomembranous colitis), and Erythromycin

- all given twice daily


What is Azaleic Acid and what is it used for?

- white powder found in wheat that kills acne bacteria and decreases keratin production

- used to treat mild-moderate acne and post-inflammatory hyperpigmentation

- give twice daily and can cause local skin irritation


What 6 oral antibiotics (T/D/M/E/Az/TPS) are used to treat acne and what adverse effects can they have?

Tetracycline/Doxacycline - photosensitive, GI distress
- DO NOT give to pregnant women or children

Minocycline - dizziness, drug-induced lupus
- DO NOT give to pregnant women or children

Erythromycin/Azithromycin - GI distress

Trimethoprimsulfamethoxazole - Steven-Johnson Synd.


What 2 hormonal agents (OC/S) are used to treat acne and what adverse effects can they have?

Oral Contraceptives: once daily - nausea/breast tender

Spironolactone - ESPECIALLY useful for women with menstrual cycle-related breakouts of acne
- contraindicated in pregnancy