Dermatologic Pharm (Wolff) Flashcards
What are the variables that affect cutaneous absorption of drugs?
Regional (ie, axilla more permeable than forearm)
Concentration gradient
Dosing schedule
Vehicles/Occlusion (both can maximize drug penetration)
What layers of the skin do the cutaneous drugs bind to receptors?
Stratum Spinosum
Basement Membrane Zone
At what point in the skin layers does the drug become absorbed into the bloodstream?
Subcutaneous Fat
Creams are a mixture of what?
Half water, half oil (oil in water) with emulsifier (ie, cetyl alcohol)
***Water evaporates
(CREAMS/OINTMENTS) spread easily, are well absorbed, and wash off with water. They are too thick to pump, so packaged in tub or tube.
Creams
***Lotions are similar to creams, just less viscous!
Creams are better than ointments for what type of skin conditions?
Oozing or wet skin conditions
Ointments are a mixture of what?
20% water in 80% oil
The oil component of ointments is made from _________ such as mineral oil or petroleum jelly.
Hydrocarbons
Ointments are greasy and are ________, meaning they stay on the surface of the skin and are not well absorbed.
Occlusive
Ointments are best for what type of skin?
Dry skin, since they trap moisture
Ointments are (MORE/LESS) likely to cause an allergic reaction than creams, which contain preservatives.
Less
What are gels made of?
Polyionic colloids expanded with water
What are pastes made of?
Mixtures of oil, water, and powder
What is the single most important measure to reduce transmission of microorganisms to other areas of body or other patients?
Hand Hygiene
What are the “Five Moments for Hand Hygiene”?
- Before touching a patient
- Before clean/aseptic procedures
- After body fluid exposure/risk
- After touching a patient
- After touching patient surroundings
How long should you wash your hands?
15-30 seconds
***Many don’t wash long enough!
T/F. Scented soap should be used for hand washing, but this does not reliably prevent microbial transmission.
False. Plain soap should be used!
Frequent hand washing may cause skin damage and irritation, so an alternative is an alcohol-based hand disinfection (hand sanny). It is rapidly effective against gram-positive, gram-negative, and viral pathogens but does not work against….
C. difficile (must use soap and water for this)
This is a component of moisturizer that forms an oily layer on top of the skin that traps water in the skin.
Emollients
- **Common ones are:
- Petrolatum
- Lanolin
- Mineral oil
- Dimethicone
This is a component of moisturizer that draws water into the outer layer of the skin.
Humectants
- **Common ones are:
- Glycerin
- Lecithin
- Propylene glycol
This is a component of moisturizer that loosens the bonds between the top layer of cells, helping dead skin cells fall off. It also helps the skin retain water, and gives it a smoother, softer feeling.
Horny substance (keratin) softeners
- **Common ones are:
- Urea
- Alpha hydroxy acids (ie, lactic, citric, glycolic)
- Allantoin
What is the skin type based on the following description of a specific moisturizer?
– Water-based moisturizer that has a light, nongreasy feel.
– Often contain lightweight oils, such as cetyl alcohol, or silicone-derived ingredients, such as cyclomethicone.
Normal skin
What is the skin type based on the following description of a specific moisturizer?
– Heavier, oil-based moisturizer that contains ingredients such as antioxidants, grape seed oil or dimethicone, which helps keep your skin hydrated.
– Petrolatum-based products are preferable for worse cases of this skin type, because they prevent water from evaporating.
Dry skin
What is the skin type based on the following description of a specific moisturizer?
– Water-based product that is labeled “noncomedogenic” to provide moisture while limiting acne breakouts.
Oily skin
What is the skin type based on the following description of a specific moisturizer?
– Has soothing ingredients such as chamomile or aloe that does not contain allergens (ie, fragrances or dyes) or acids to minimize skin irritation.
Sensitive skin
What is the skin type based on the following description fo a specific moisturizer?
– Oil-based moisturizer that contains petrolatum as the base to keep skin hydrated plus antioxidants or alpha hydroxy acids to combat wrinkles.
Mature skin
(UVA/UVB) radiation causes most erythema/sunburn and skin aging and photocarcinogenesis.
UVB (280-320 nm)
(UVA/UVB) radiation causes skin aging and cancer.
UVA (320-400 nm)
These are chemical compounds that absorb UV light.
Sunscreen
In sunscreen, _______ and its esters are active in UVB range (280-320 nm).
PABA (p-aminobenzoic acid)
In sunscreen, ________ have a wider range of 250-360 nm but are less effective than PABA.
Benzophenones
In sunscreen, _________ are active in UVA range, particularly useful for conditions such as drug-induced photosensitivity and cutaneous lupus erythematosus.
Dibenzoylmethanes
This is the term for opaque materials that reflect light, a classic example being titanium oxide.
Sunshades
What is Sun Protection Factor (SPF)? What is the highest it can be?
SPF = Ratio of minimal erythema dose with sunscreen to the minimal erythema dose without sunscreen
Limited to 50+ by FDA
This is a broad-spectrum antimicrobial agent widely used in homes and hospitals due to general efficacy on skin (including oral mucosa) and low irritability.
Chlorhexidine
What is the target and mechanism of action of Chlorhexidine?
Cytoplasmic (inner) membrane
Low concentrations will affect membrane integrity.
High concentrations cause congealing of cytoplasm.
What action does Chlorhexidine have on bacterial spores?
- Prevents development of spores
- - Inhibits spore outgrowth but not germination
What action does Chlorhexidine have on mycobacteria?
– Mycobacteriostatic (mechanism unknown)
What action Chlorhexidine have on other non-sporulating bacteria?
– Membrane-active agent causing protoplast and spheroplast lysis
– High concentrations cause precipitation of proteins and nucleic acids
What action does Chlorhexidine have on yeasts?
– Membrane-active agent causing protoplast lysis and intracellular leakage
– High concentrations cause intracellular coagulation
What action does Chlorhexidine have on viruses?
- Low activity against many viruses
- - Lipid-enveloped more sensitive than non-enveloped
What action does Chlorhexidine have on protozoa?
– Has activity against trophozoites (less toward cysts)
What is the list of organisms from most resistant to least resistant of antiseptics and disinfectants?
Prions (most resistant) Coccidia Spores Mycobacteria Cysts Small non-enveloped viruses Trophozoites Gram-negative bacteria Fungi Large non-enveloped viruses Gram-positive bacteria Lipid-enveloped viruses (least resistant)
Describe wound healing by first intention (cut).
1) Inflammatory Phase – 24 hours, scab forms and neutrophils and clot is present.
2) Proliferative Phase – 3-7 days, macrophages and other cells are present. Mitoses occurs and new capillary is forming.
3) Remodeling Phase – Weeks, fibrous union of the skin back together.
Describe wound healing by second intention (gouge).
Process are basically the same as first intention, but the injury is filling from the bottom up.
– Larger scab (clot)
– Inflammation more intense because of more necrotic debris, exudate, and fibrin to remove.
– Larger amounts of granulation tissue – larger defect (scar).
– Involves wound contraction.
Are antiseptic wash solutions such as dilute iodine, chlorhexidine, or hydrogen peroxide effective against bacteria?
Generally not necessary to use because they minimal action. Could potentially impede wound healing through toxic effects on normal tissue.
T/F. Antibiotic therapy should be reserved for wounds that appear clinically infected. No evidence shows that antibiotic use as prophylaxis or healing of non-infected wounds is improved.
True
In primary closure of surgical wounds in high-risk patients, poor _______ ______ is significantly associated with worse outcomes.
Glycemic Control
Postoperative hyperglycemia is frequent after elective _________ surgery in nondiabetic patients. Even a single postoperative elevated glucose value is adversely associated with morbidity and mortality.
Colorectal
It’s important to ensure adequate oxygenation. Usual reason for inadequate oxygenation is local vasoconstriction due to sympathetic overactivity. Common causes of this are…
- Blood volume deficit
- Unrelieved pain
- Hypothermia
T/F. It’s important to ensure adequate nutrition. We would most often suspect malnutrition in patients with chronic illnesses, inadequate societal support, multi systemic trauma, or GI or neurons problems that may lead to impaired intake. We must address protein-calorie malnutrition and deficiencies of vitamins and minerals.
True
Wound debridement removes dead tissue and debris, and promotes wound healing by limiting ________ production and conserving the local resources needed for healing.
Protease
This type of wound debridement should be routine since it flushes bacteria and removes loose material.
Low-Pressure Irrigation with Normal Saline
This type of wound debridement is appropriate for removing large areas of necrotic/infected tissue.
Surgical Debridement
This type of wound debridement uses a variety of products and gives mixed results. Collagenase may promote endothelial cell and keratinocyte migration for angiogenesis and epithelialization.
Enzymatic Debridement
This type of wound debridement uses maggots. Maggot therapy has negative perceptions, but does result in liquefaction of necrotic tissue while leaving healthy tissue intact. However, pressure ulcer healing time is not consistently reduced.
Biologic Debridement
This is a platelet-derived growth factor that promotes cell proliferation and angiogenesis. It is the ONLY agent approved for treatment of chronic diabetic foot ulcers.
Becaplermin
Becaplermin has a black box warning for malignancy when how much is used?
Use of >3 tubes increases risk of malignant complications by about 4x
Epidermal growth factor (DOES/DOES NOT) significantly improve epithelialization.
Does Not
What is the general principle for wound dressings?
Wounds should be kept moist, and should NOT be exposed to air (as done historically)
Occluded wounds heal 40% faster and have less scarring. The wounds are exposed to their own fluid, a mix of…
Metalloproteases and Cytokines
Hydrogels are best used for the _________ stage.
Debridement
Foam and low-adherence dressings are used for the _________ stage.
Granulation