Dermatology, Pharmacology and Prescribing Flashcards
Who licences medication in scotland?
SMC - Scottish medicines consortium
What are the causes of prescription errors?
•Lack of knowledge
–About the patient, the medication, allergies
- Mistake writing/generating the prescription
- Poor communication
- No local or national guidelines
- Pharmacy/medicine info service
What is the definition of pharmacokinetics and pharmacodynamics?
Pharmacokinetics - the effect of the body on the drug/getting the drug to site of action
Pharmacodynamics - the effect of the drug on the body once it gets to site of action
What are the factors that should be considered regarding pharmacodynamics in different patients?
–Age of patient
–Pregnancy risk (some drugs may be teratogenic)
–Drug interactions
–Pharmacogenetics
Who is more likely to stick to their medication?
–Female
–Married
–Employed
–Not paying for their prescriptions
–Increasing age
Generally educated patients.
What factors are associated with poor adherence/compliance?
- Psychiatric co-morbidities
- Slower acting agents
- Multiple applications per day
- Lack of patient education
- Cosmetic acceptability of treatments
- Unintentional non-adherence
In Derm, drugs can be given X or Y
X = TOPICALLY
Y = SYSTEMICALLY
Topical Drugs are made up of X and Y
X = VEHICLE
Y = ACTIVE DRUG
What is a vehicle when discussing topical drugs?
Pharmacologically inert, physically and chemically stable substance that carries the active drug
Name some types of vehicle?
Solution
Paste
Cream
Spray powder
Lotion
Shampoo
Gel
Ointment
Foam
Paint
Tape
Give examples of active drugs given topically?
Corticosteroid
Chemotherapy
Antibiotic
Parasiticidals
Antiviral
Coal Tar
Dithranol
Anti-inflammatory
Vitamin analogues
Salicylic acid
What factors affect absorption?
- Concentration
- Base/vehicle
- Chemical properties of the drug
- Thickness and hydration of stratum corneum
- Temperature
- Skin site
- Occlusion
What is the function of topical steroids?
Anti-inflammatory
Immunosuppressice
Also vasoconstrict
Also inhibit vascular permeability
What is the finger tip unit?
Topical Steroids often administered in fingertip units.
About 0.5 grams - should treat the area double the size of one hand
What conditions should topical steroids be used for vs NOT used for?
Used for - Psoriasis and Eczema
NOT used for - Acne Vulgaris and Rosacea
What are the side effects of topical steroids?
- Thinning /atrophy of skin (especially in thin areas eg eyelids)
- Striae
- Bruising
- Hirsutism - thick black male like hair in females
- Telangiectasia - thin red thread like vessels
- Acne/rosacea/perioral dermatitis
- Glaucoma and cataracts
- Systemic absorption
What skin condition can arise after stopping a course of topical steroids?
Perioral dermatitis
Treatment for which is stopping steroids and using emolient
What are the systemic treatments used in dermatology?
Retinoids
Traditional immunosuppressants
Biologics (also immunosuppressive)
What are retinoids and what are their function?
Vitamin A anologues
They normalise keratinocyte function
Anti-inflammatory and anti-cancer effects
What common derm conditions can Retinoids be used for?
Acne Vulgaris
Acne Rosacea
What are the four different oral agents (retinoids) and their uses
Acne - Isotretinoin
Psoriasis - acitretin
Cutaneous T cell lymphoma - bexarotene
Hand eczema - alitretinoin
What are the risks associated with retinoids?
Remember you need to do regular blood tests to check LFTs
Teratogenic - DO NOT GIVE TO FEMALES OF CHILD BARING AGE unless confirmed on birth control
Cheilitis (dry lips)
Xerosis (dry skin)
Increase in transaminases
Increase in triglycerides
Rarely psychiatric, eye, bone side effects
What are the immunosuppressants used for the treatment of inflammatory skin disorders?
- Oral steroids
- Azathioprine
- Ciclosporin
- Methotrexate
- Mycophenolate mofetil
What are the risks associated with immunosuppressants?
Malignancy
Serious unfection
Because they have broad spectrum of action
What are the blood tests needed in association with using immunosuppressants?
–FBC (esp in methotrexate and azathioprine)
–Renal function (esp ciclosporin)
–Liver function (esp methotrexate)
How are biologics made?
Genetically engineered proteins derived from human genes
Designed to inhibit specific portions of the immune system
What do the suffix’es cept and mab mean?
cept - genetically engineered fusion protein
mab - monoclonal antibodies
What are the infixes that immediately precede mab?
zu - humanised
ix - chimeric
u - fully human
li/l - immunomodulator
•E.g.adalimumab = immunomodulator fully human monoclonal antibodies
Give an example of a biologic that is used to treat plaque psoriasis in the UK
Etanercept
Adalimumab
Infliximab
For chronic spontaneous utricaria - omalizumab
What are the risks associated with biologic agents?
•Risk of infection
–TB reactivation
–Serious infection
–Avoid live vaccines eg yellow fever (but can have flu vax)
- Risk of malignancy
- TNF inhibitors – risk of demyelination
Biologics have been described as revolutionary for what condition?
Melanoma - ~20% 5 year survival in stage 4 disease
