dermatology pharmacology and prescribing Flashcards
What is pharmacokinetics
Effect of the body on the drug
What is pharmacodynamics
Effect of the drug on the body
What is topical therapy
Medication applied to the skin
What is a vehicle in topical therapy
How you get the drug on the skin
What affects topical absorption
Concentration
vehicle used
chemical properties of the durg
hydration of the stratum corneum - outer layer
temperature
skin site
occlusion
What is the function of topical steroids
Anti-inflammatory and immunosuppressive function
How do topical steroids work
Regulate pro inflammatory cytokines
Suppress fibroblast, endothelial and leukocyte function
Vasoconstriction
Inhibit vascular permeability
What is a finger tip unit
Enough topical dosage on the fingertip should be around 0.5g and enough to treat double the size of a hand
What are the side effects of topical steroids
Skin thinning
Striae
bruising
hirsutism
Telangiectasia - dilatation of capillaries causing spider like appearance
Acne
Glaucoma
cataracts
Why do topical steroid doses have to be increased
The skin develops a tolerance to the topical steroids
What are the systemic treatments in dermatology
Retinoids
immunosuppressants
Biologics - can also be immunosuppresive
What are retinoids and what is their effect
Vitamin A analogues
Anti-inflammatory and anti-cancer effects
normalise the function of keratinocytes
What are retinoids effective in the treatment of
Acne - Isotretinoin
Psoriasis - acitretin
cutaneous T cell lymphoma - bexarotene
hand eczema - alitretinoin
What are retinoids contraindicated in
Pregnancy - they are teratogens
What are the side effects of retinoids
Cheilitis - dry lips
Xerosis - dry skin
Eye and bone side effects
Increased transaminases and triglycerides
What immunosuppressants are used to treat inflammatory skin disorders
Oral steroids
Azathioprine
ciclosporin
methotrexate - DMARD
mycophenolate mofetil
What are the side effects of immunosuppressants
risk of malignancy and infection
What is required during immunosuppressant therapy
Regular blood tests :
FBC - in methotrexate and azathioprine
Renal function - in ciclosporin
Liver function - in methotrexate
What are the side effects of biologics
Risk of infection
TB reactivation
Increased malignancy risk
TNF inhibitors have the risk of demyelinations
What should be avoided when on biologics
Live vaccines
What is the new main treatment of melanoma
Biologics:
If BRAF 600 mutation : Vemurafenib and dabrafenib
Immunotherapies : iplumuumab and pembrolizumab
