Pharmacology

Question 1

what are the three major routes of drug administration in the skin?

Answer 1

topical
transdermal
subcutaneous

Question 2

what effect do topical treatments have?

Answer 2

local

Question 3

what effect to transdermal and subcutaneous treatments have?

Answer 3

systemic

Question 4

what is the most important barrier to drug penetration in the skin?

Answer 4

the stratum corneum (keratin layer)

Question 5

what are the two routes of drug diffusion across the stratum corneum?

Answer 5

intercellular

transcellular

Question 6

what is the equation to determine the rate of absorption of a topical drug?

Answer 6

J= Kp x Cv

Kp = permeability coefficient
Cv =concentration of drug in vehicle

Question 7

does a lipophilic drug in a lipophilic vehicle absorb well?

Answer 7

ish

Question 8

does a lipophilic drug in a hydrophilic vehicle absorb well?

Answer 8

yes

Question 9

does a hydrophilic drug in a lipophilic vehicle absorb well?

Answer 9

kinda - weak

Question 10

does a hydrophilic drug in a hydrophilic vehicle absorb well?

Answer 10

nope

stays on the skin

Question 11

what can enhance the solubility and absorption of a topical drug?

Answer 11

excipients

Question 12

name an excipient that can. be added to topical drugs

Answer 12

propylene glycol

Question 13

how well absorbed are topically applied drugs?

Answer 13

poorly absorbed

only a small amount moves into the skin

Question 14

name two things that can increase how much of a topical drug partitions into the skin

Answer 14

hydration of the skin by occlusion i.e. appropriate vehicle or wrapping the area in cling film

inclusion of excipients to increase solubility

Question 15

what causes increased partitioning of topical drugs?

Answer 15

reduction in the barrie function of the stratum corneum

Question 16

name three conditions that topical glucocorticoids are often used to manage

Answer 16

atopic eczema
psoriasis
pruritus

Question 17

what are the four categories of topical glucocorticoids?

Answer 17

mild
moderate
potent
very potent

Question 18

name three formulations that topical glucocorticoids can be administered in

Answer 18

lotions
creams
ointments

Question 19

what causes steroid rebound due to topical glucocorticoid use?

Answer 19

glucocorticoid receptor down regulation

Question 20

name a possible systemic effect of topical glucocorticoids

Answer 20

HPA axis depression

Question 21

what skin changes can be caused by topical glucocorticoids?

Answer 21

skin atrophy
steroid rosacea
stretch marks
telangiectasia

Question 22

what is the proper term for stretch marks?

Answer 22

striae atrophica

Question 23

are glucocorticoids lipophillic or lipophobic

Answer 23

lipophillic

Question 24

how do glucocorticoids enter cells?

Answer 24

via diffusion across the plasma membrane

Question 25

describe the subcutaneous route of drug administration

Answer 25

drug is delivered by a needle inserted into adipose tissue directly underneath the skin - the subcutaneous tissue

Question 26

what effect does topical administration have on drug metabolism?

Answer 26

allows drugs to avoid first pass metabolism

Question 27

how can transdermal drug delivery be achieved?

Answer 27

drug incorporated into an adhesive patch that is applied to the epidermis

Question 28

describe the properties of a drug that would be suitable for administration via the transdermal route

Answer 28

low molecular weight moderately lipophillic potent relatively brief half life

Question 29

name some drugs that can be administered via the transdermal route

Answer 29

``` scopolamine nicotine GTN fentanyl buprenorphine oestradiol ```