Dermatology Pharmacology and Prescribing Flashcards
Who must medication be approved by to be licensed in the UK for dermatology?
MHRA (Medicines and Healthcare Products Regulatory Agency)
EMA (European Medicines Agency)
What are the different kinds of medicines without liscence?
- Unlicensed
- Not approved for use in UK
- ‘Off label’
- Licensed medication that is being used for an unlicensed indication
- ‘Specials’
- Unlicensed dermatological preparations
- No strong evidence base but clinically effective
What does ‘off label’ medication mean?
Licensed medicatio that is being used for an unlicensed indication
What are some causes of prescription error?
- Lack of knowledge
- About the patient, medication or allergies
- Mistake writing/generating prescription
- Poor communication
- No local or national guidelines
- Pharmacy/medicine info service
What is pharmacology?
Branch of medicine concerned with the uses, effects and modes of action of drugs
What is pharmacokinetics?
Effect of the body on the drug
What is pharmacodynamics?
Effect of the drug on the body
What are the 4 things that should be considered in relation to pharmacokinetics?
Absorption
Distribution
Metabolism
Excretion
What are some different kinds of routes of administration for dermatology medications?
Topical
Oral
What is meant by pharmacodynamics being the effect of the drug on the body?
Individual variation in response
What needs to be considered when thinking about the pharmacodynamics of a drug?
- Age of patient
- Pregnancy risk
- Drug interactions
- Pharmacogenetics
What are some factors associated with poor aherence to taking medication?
- Psychiatric co-morbidities
- Slower acting agents
- Multiple applications per day
- Lack of patient education
- Cosmetic acceptability of treatments
- Unintentional non-adherence
What is topical therapy?
Medication applied to the skin
What does topical medication contain?
Vehicle and active drug
What is a vehicle in topical medication?
Pharamcological inert, physically and chemically stable substance that carries the active drug
What are factors that affect absorption?
- Concentration
- Base/vehicle
- Chemical properties of the drug
- Thickness and hydration of stratum corneum
- Temperature
- Skin site
- Occlusion
What are some different kinds of vehicles?
- Solution
- Cream
- Lotion
- Gel
- Foam
- Tape
- Paste
- Spray powder
- Shampoo
- Ointment
- Paint
What are some examples of drugs that can be used topically?
- Corticosteroid
- Antibiotic
- Antiviral
- Dithranol
- Vitamin analogues
- Chemotherapy
- Parasiticidals
- Coal Tar
- Anti-inflammatory
- Salicylic acid
- Topical immunomodulators
- Next generation drug
What properties do topical steroids have?
Anti-inflammatory and immunosuppressive properties:
- Regulate pro inflammatory cytokines
- Suppress fibroblast, endothelial and leukocyte function
- Vasoconstriction
- Inhibit vascular permeability
What can be refered to for guidance on how much of a drug to prescribe?
BNF (British National Formulary)
What is a ‘finger tip’ unit?
About 0.5g
Should be used to treat an area the size of one hand
Useful in young children
What are some possible side effects of topical steroids?
- Thinning/atrophy
- Striae
- Bruising
- Hirsutism
- Telangiectasia
- Acne/rosacea/perioral dermatitis
- Glaucoma
- Systemic absorption
- Cataracts
What are some systemic treatments used in dermatology?
- Retinoids
- Traditional immunosuppressants
- Biologics (also immunosuppressive)
What are retinoids?
These are vitamin A analogues:
- Normalise keratinocyte function
- Anti-inflammatory and anti-cancer effects
What effects do retinoids have?
- Normalise keratinocyte function
- Anti-inflammatory and anti-cancer effects
What are retinoids useful to treat?
- Acne
- Isotretinoin
- Psoriasis
- Acitretin
- Cutaneous T cell lymphoma
- Bexarotene
- Hand eczema
- Alitretinoin
Why must patients be selective careful for retinoids?
They are teratogenic
What are some possible side effects of retinoids?
- Cheilitis (dry lips) and xerosis (dry skin)
- Increases transaminases and triglycerides
- Rarely psychiatric, eye and bone side effects
What is the medical term for dry lips?
Cheilitis
What is the medical term for dry skin?
Xerosis
What are immunosuppressants used to treat?
Inflammatory skin disorders
What are some examples of immunosuppressants?
- Oral steroids
- Azathioprine
- Ciclosporin
- Methotrexate
- Mycophenolate mofetil
What are the risks of taking immunosuppressants?
Malignancy and serious infection
What must be done regulatory when taking immunosuppressants?
Need regular blood test monitoring, in particular:
- FBC (especially in methotrexate and azathioprine)
- Renal function (especially ciclosporin)
- Liver function (especially methotrexate)
What are biologics?
Next generation in treatment of inflammatory conditions:
- Genetically engineered proteins derived from human genes
- Designed to inhibit specific components of the immune system
- Very effective, but expensive
What do biologics do?
Inhibit specific components of the immune system
What are the 2 suffixes of biologics?
- cept
- mab
What does the suffix -cept indicate?
It is a receptor fusion
What does the suffix -mab indicate?
Monoclonal antibodies
What are some infixes of biologics that immediately preced -mab?
- –zu (humanised)
- –ix (chimeric)
- –u (fully human)
- –li-/-l- (immunomodulatory)
What does the infix -zu indicate in biologics?
Humaised
What does the infix -ix indicate in biologics?
Chimeric
What does the infix -u indicate in biologics?
Fully human
What does the infix -li-/-l- inficate in biologics?
Immunomodulatory
What are some currently licenced biologics for plaque psoriasis in the UK?
What is a licenced biologic for chronic spontaneous urticarial?
Omalizumab
What is a licenced biologic for eczema?
Dupilumab
When taking biologics, what are you at risk of?
Risk of infection:
- TB reactivation
- Serious infection
- Avoid live vaccines
Risk of malignancy
TNF inhibitors cause risk of demyelination
What is a revolutionary treatment option for advanced melanoma?
Biologics
20% 5 year survival in stage 4 disease
What are some targeted treatments (biologics) for advanced melanoma?
- If BRAF 600 mutation
- Vemurafenib
- Dabrafenib
- Immunotherapies
- Ipilumamab
- Pembrolizumab
- Nivolumab
Where can reliable information about drugs be found?
- SPC
- SMC
- BNF
