Dermatologic Pharmacology (Part 1) Flashcards
What are 4 variables that affect the rate of cutaneous absorption of products?
regional, concentration gradient, dosing schedule =, and vehicles/ occlusion (both can maximize drug penetration)
what is the mixture of creams vs ointments?
creams are a mixture of half water and half oil with emulsifier and ointments are a mixture of about 20% water and 80% oil
what are the emulsifiers used on creams?
cetyl alcohol
what are the general characteristics of creams?
they spread easily (i.e. good for large areas), are well absorbed, and wash off with water; too thick to pump;
when are creams better than ointments?
creams are better for oozing/ “wet” skin conditions
what are the oil components that are in ointments?
hydrocarbons such as mineral oil or petroleum jelly
what are the general characteristics of ointments?
they feel greasy and are “occlusive” meaning that they stay on the surface of the skin and are not well absorbed
when are ointments better than creams?
best used on dry skin since they trap moisture; they provide for more complete absorption of the active ingredient or medication
what is special to note about ointments and adverse effects?
they are less likely to cause an allergic reaction than creams, because creams contain preservatives
how long should you wash your hands?
15-30 seconds
alcohol-based hand disinfection is rapidly effective against what?
gram-positive, gram-negative, and viral pathogens; not effective against C. difficile
what are the 3 components in moisturizer?
emollients, humectants, and horny substance softeners
what are emollients?
they form an oily layer on top of the skin that traps water in the skin
what are 4 examples of emollients?
petrolatum, lanolin, dimethicone, and mineral oil
what are humectants?
they draw water into the outer layer of the skin
what are 3 examples of humectants?
glycerin, lecithin, and propylene glycol
what are horny substance softeners?
they loosen the bonds between the top stratum corneum layer of skin which helps the dead skin cells fall off, helps the skin retain water, and gives it a smoother, softer feeling in thicker areas
what are 4 examples of horny substance softeners?
alpha hydroxyacids, salicylic acid, urea, and allantoin
what type of moisturizer should be used on normal skin type?
water-based moisturizer that has a light non-greasy feel; these moisturizers often contain light weight oils
what type of moisturizer should be used on dry skin?
choose a heavier, oil-based moisturizer
what products are preferred for very dry cracked skin?
petrolatum-based products since they prevent water from evaporating
what type of moisturizer should be used for oily skin?
water based product that is labeled “noncomedogenic”
what moisturizer should be used for sensitive skin?
one with soothing ingredients such as chamomile or aloe that does not contain potential allergens (fragrances of dyes) or acids
what moisturizer should be used for mature skin?
oil-based moisturizer that contains petrolatum as the base to keep skin hydrated plus antioxidants or alpha hydroxyacids to combat wrinkles
what does UVB radiation cause?
erythema/sunburn and skin aging and photocarcinogensis
what does UVA radiation cause?
skin aging and cancer
what 2 active ingredients are used in sunscreen?
benzophenones and dibenzoylmethanes
what was the classic active ingredient in sunscreen but is now not commonly used?
PABA- not used now due to hypersensitivity concerns
what is an example of a benzophenon?
oxybenzone
what is an example of dibenzoylmethane?
avobenzone
what are dibenzoylmethanes particularly useful for?
conditions such as drug-induced photosensitivity and cutaneous lupus erythematous
what are sunshades and what is an example?
opaque materials that reflect light; classic example is titanium dioxide
what is chlorhexidine?
a broad-spectrum antimicrobial agent that is widely used in homes and hospitals due to safety, general efficacy on skin, and low irritability
what is the general hierarchy to resistance to antiseptic and disinfectants?
prions–> protozoan (cryptosporidium oocysts)–> C. difficle spores
what are 5 examples of antibiotic resistance mechanisms of biofilms?
they limit penetration, they have persistent cells, they neutralize antibiotics, they have enzymes that break down antibiotics, and they slow growth making them harder to kill
