Pharmacology Flashcards
What are the 3 major routes of drug administration through the skin?
Topical, transdermal, subcutaneous
Which route of drug administration is mainly used for local effect? Which are used for prolonged systemic effects?
Local = topical, Systemic = transdermal and subcutaneous
What is the most important barrier to drug penetration?
Keratin layer
What are adjacent corneocytes held together by?
Corneodesmosomes
Both local and systemic drugs must cross the keratin layer. True or false?
True
Penetration of the keratin layer normally only allow diffusion of which drugs?
Small, hydrophobic drugs
The topical route is mainly used for treatment of what?
Superficial skin disorders
What do keratolytic drugs do? When are they used?
Break down the keratin layer- used in warts
What are 2 important factors which influence the rate and extent of absorption of a topically applied drug?
Solubility of the drug in the vehicle, movement of the drug from the vehicle to the keratin layer
Transdermal drug delivery is driven by what?
Diffusion
What type of drug dissolved in what type of vehicle will be the most effective at getting through the keratin layer?
Lipophilic drug in a lipophilic or hydrophobic vehicle
Only the drug which is dissolved in the vehicle is able to be absorbed. True or false?
True
Increased partitioning of a drug results from what?
Reduction in barrier function in the keratin layer
What are the relative potencies of drugs in thick and thin skin?
Thick skin = high potency, thin skin = low potency
What does it mean for a drug to have high potency?
Evokes a response at a low concentration
Which is more potent, hydrocortisone butyrate or hydrocortisone acetate?
Hydrocortisone butyrate
Corticosteroids have what effect on blood vessels?
Vasoconstriction
Systemic side effects do not occur with topical administration of steroids. True or false?
False, it is less likely but systemic side effects can still occur
Which is more potent, and ointment or a cream?
Ointment