Pharmacology - Dermatology Flashcards
true or false: immunologically mediated skin reactions are dose dependent
false
true or false: non immunologically mediated skin reactions can be dose dependent
true
how to urticarial drug eruptions usually arise?
IgE mediated hypersensitivity
drug induced mast cell degranulation
which drugs tend to cause pustular/bullous drug reactions?
glucocorticoids
androgens
hypertensives
which drugs are commonly associated with fixed drug eruptions, that are well-demarcated and round?
tetracycline antibiotics
paracetamol
NSAIDs
what are the three major routes of drug administration through the skin?
topical
transdermal
subcutaneous
what is the single most important barrier to drug administration?
stratum corneum
is the stratum corneum hydrophilic or lipophilic?
lipophilic
means it absorbs lipid soluble drugs
what are vehicles that drugs are often found in?
pharmacologically inactive substances that carry the drug
list some examples of drug vehicles
ointments creams gels lotions pastes
true or false: a drug must exit its vehicles if it is to penetrate the stratum corneum
true
true or false: the higher the Km of a drug, the better it will enter the skin
true
true or false: a lipophilic drug in a hydrophilic vehicle will absorb poorly in the skin
false
they absorb very well
true or false: a lipophilic drug in a lipophilic vehicle will absorb very well in the skin
false
why won’t a hydrophilic drug in a lipophilic vehicle absorb very well?
cant penetrate the stratum corneum
what enhances the absorption of a drug in the skin?
excipients
what are creams?
semi solid emulsion of oil and water containing an emulsifier and a preservative
true or false: creams are cooling and greasy
false
not greasy
what is the danger of the preservative in creams?
may cause an allergic reaction
what are ointments?
semi-solid mix of grease and oil containing soft paraffin
what is the benefit of ointments?
effective at restricting transepidermal water loss
what is the downside of ointments?
they are not cosmetically attractive as they are very greasy
what are lotions?
a suspension of medication in a liquid
what are gels?
a thickened aqueous solution containing high molecular weight polymers
what is the downside of pastes?
they are stiff and difficult to apply
what is the function of emollients?
they enhance the hydration of the epidermis
what conditions are emollients used for?
dry scaly conditions such as eczema
when are wet wraps frequently used and how are they applied?
for very dry skin
wrapped around moisturised skin to lock in the moisture
what are the three actions of topical steroids on the skin?
anti inflammatory
anti proliferative
vasoconstrictive
name a mild steroid for skin disease
hydrocortisone
name a moderate steroid for skin disease
modrasone
name a potent steroid for skin disease
mometasone
name a very potent steroid for skin disease
clobetasol
how many grams of steroid are equivalent to one fingerprint unit?
0.5g
how many hand areas are one fingerprint unit?
two
what is meant by tachyphylaxis to steroid?
the steroid becomes less effective despite a maintained dosage
what conditions is a potassium permanganate bath useful for?
exudative eczema
pompholyx
what is pompholyx?
exudative eczema restricted to the hands and feet
forms watery blisters
very itchy
name topical antibiotics used for acne
tetracycline
clindamycin
erythromycin
what is the main antibiotic used for rosacea?
metronidazole
list some antipruritics
menthol
capsaicin
phenol
what are keratolytics used for?
softening keratin
name a keratolytic
salicylic acid
besides emollients, what other drugs can be used for psoriasis?
coal tar
vitamine D analogues
keratolytics
topical steroids
which cream has been shown to be effective for pre cancerous skin lesions?
aldara cream
imiquimod
