Dermatology Pharmacology and Prescribing Flashcards
How much of hospital admissions are due to adverse drug reactions?
3-6%
Half of these are preventable
What makes medication licensed?
Approved for use in UK by MHRA and EMA
High standards
Trial evidence to show positive effect
SMC submission - Scottish Medicines Consortium
What are medicine without licence?
Unlicensed - not approved use in the UK
Off label - licensed medication that is being used for non-licensed indication
Specials - unlicensed dermatological preparations
What are some factors associated with poor adherence?
Psychiatric co-morbidities, slower acting agents, multiple applications per day, lack of patient education, cosmetic acceptability of treatments and unintentional non-adherence
What is pharmacokinetics?
The effect of the body on the drug
What is pharmacodynamics?
The effect of the drug on the body
What is included in pharmacokinetics?
Route of administration
Distribution
Metabolism - esp. in liver disease
Excretion - esp. in renal disease
What is involved in pharmacodynamics?
Individual response to drug
Patient age, pregnancy risk, drug interactions and pharmacogenetics
What is a vehicle in pharmacology?
Pharmacologically inert, physically and chemically stable substances that carries the active drug
What is topical therapy?
Medication applied to the skin
Vehicle + active drug
What are some factors which affect topical absorption?
Concentration, base/ vehicle, chemical properties, thickness and hydration of stratum corneum, temp., skin site and occlusion
What are types of vehicles of drugs?
Solution, cream, lotion, paste, paint, spray, shampoo, gel, foam, ointment and tape
What are some drugs which are used topically?
Corticosteroid, antibiotic, antiviral, dithranol, vitamin analogues, chemo, parasiticidal, coal tar, anti-inflammatory and salicylic acid
Describe topical steroids
Anti-inflammatory and immunosuppressive properties
Regulate pro-inflammatory cytokines
Supress fibroblast, endothelial and leukocyte function
Vasoconstriction and inhibit vascular permeability
What is a finger tip unit?
0.5g - can treat area double the size of one hand
Useful for children and charts are available for ages
What are some side effects of topical steroids?
Thinning, striae, bruising, hirsutism, telangiectasia, acne, glaucoma, systemic absorption and cataracts
What are some systemic treatments in dermatology?
Retinoids
Traditional immunosuppressants
Biologics
Describe retinoids
Vitamin A analogues - normalise keratinocyte function and anti-inflammatory and anti-cancer effects
4 different molecules used orally in dermatology
What are retinoids effective in?
Acne - isotretinoin
Psoriasis - acitretin
Cutaneous T cell lymphoma - bexarotene
Hand eczema - alitretinoin
What are the side effects of retinoids?
Teratogenic
Cheilitis (dry lips) and xerosis (dry skin)
Increased transaminases and triglycerides
Rare - psychiatric, eye and bone side effects
Describe immunosuppressants
Treatment of inflammatory skin disorders
Oral steroids, azathioprine, ciclosporin, methotrexate and mycophenolate mofetil
Risk of malignancy and serious infection
What monitoring is needed for immunosuppressants?
FBC
Renal function
Liver function
Describe biologics
Next generation of treatment for inflammatory conditions
Genetically engineered proteins derived from human genes
Designed to inhibit specific components of immune system
What does the suffix -cept and -mab mean for biologics?
-cept indicates it is a receptor fusion
-mab is used to denote monoclonal antibodies
What are some infixes for biologics?
Zu - humanised
Ix - chimeric
U -fully human
Li/-l- - immunomodulator
What are some current licensed biologics for dermatology conditions?
Psoriasis, Hidradenitis suppurativa, chronic spontaneous urticaria, atopic eczema and pemphigus
What are the risks of biologics?
Risk of infection - TB activation, serious infection and avoid live vaccines
Risk of malignancy
TNF inhibitors - risk of demyelination
What is the targeted treatment for melanomas?
If BRAF 600 mutation - Vemurafenib and Dabrafenib
Immunotherapies - Ipilumumab and Pembrolizumab
