Dermatology pharmacology and prescribing

Question 1

what makes a medication liscenced?

Answer 1

Approved for use in UK either by
MHRA – Medicines and Healthcare Products Regulatory Agency
EMA – European Medicines Agency
High standards of safety and quality
Trial evidence to show positive effect
SMC submission
Scottish Medicines Consortium

Question 2

when is medication not liscenced?

Answer 2

Unlicensed
Not approved for use in the UK
‘Off label’
A licensed medication that is being used for an unlicensed indication
‘Specials’
unlicensed dermatological preparations
Long history of use, no strong evidence base but clinically effective.

Question 3

what are causes of prescription errors?

Answer 3

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

Question 4

what factors are associated with poor adherence?

Answer 4

Psychiatric co-morbidities
Slower acting agents
Multiple applications per day
Lack of patient education
Cosmetic acceptability of treatments
Unintentional non-adherence

Question 5

what is pharmacokinetics?

Answer 5

The effect of the body on the drug

Question 6

what is pharmacodynamics?

Answer 6

The effect of the drug on the body

Question 7

what needs to be thought about in terms of pharmacokinetics?

Answer 7

Need to think about route of administration
topically where possible
If oral, optimal absorption important

Distribution – where the drug goes
Metabolism – especially in liver disease
Excretion – especially in renal disease

Question 8

what needs to be thought about in terms of pharmacodynamics?

Answer 8

Individual variation in response
Think about
Age of patient
Pregnancy risk
Drug interactions
Pharmacogenetics

Question 9

what is topical therapy?

Answer 9

Medication applied to the skin
Vehicle + active drug

Vehicle: pharmacologically inert, physically and chemically stable substance that carries the active drug

Question 10

what factors effect topical absorption?

Answer 10

Concentration
Base/vehicle
Chemical properties of the drug
Thickness and hydration of stratum corneum
Temperature
Skin site
Occlusion

Question 11

what are examples of drugs that are used topically?

Answer 11

Corticosteroid Chemotherapy
Antibiotic Parasiticidals
Antiviral Coal Tar
Dithranol Anti-inflammatory
Vitamin analogues Salicylic acid

Question 12

what are topical steroids?

Answer 12

Anti- inflammatory and immunosuppressive properties
Regulate pro inflammatory cytokines
Suppress fibroblast, endothelial, and leukocyte function
Vasoconstriction
Inhibit vascular permeability

Question 13

what do topical steroids do?

Answer 13

Regulate pro inflammatory cytokines
Suppress fibroblast, endothelial, and leukocyte function
Vasoconstriction
Inhibit vascular permeability

Question 14

how are units of topical steroids measured for children especially?

Answer 14

About 0.5 g

Should treat area double the size of one hand

Useful in young children

Charts available for age

Question 15

what are side effects of topical steroids?

Answer 15

Thinning /atrophy
Striae
Bruising
Hirsutism
Telangiectasia
Acne/rosacea/perioral dermatitis
Glaucoma
Systemic absorption
Cataracts

Question 16

what are systemic treatments in dermatology?

Answer 16

Retinoids
Traditional immunosuppressants
Biologics (also immunosuppressive)

Question 17

what are retinoids?

Answer 17

Vitamin A analogues
Normalise keratinocyte function
Anti inflammatory and anti cancer effects
Four different molecules used orally in dermatology

Question 18

when is use of retinoids effective?

Answer 18

Acne isotretinoin
Psoriasis acitretin
Cutaneous T cell lymphoma bexarotene
Hand eczema alitretinoin

Question 19

can retinoids be used in pregnant patients?

Answer 19

Careful patient selection

Question 20

what are side effects of retinoids?

Answer 20

Cheilitis(dry lips) and xerosis (dry skin)
↑transaminases, ↑triglycerides
Rarely psychiatric, eye, bone side effects

Question 21

what are immunosuppressants?

Answer 21

Treatment of inflammatory skin disorders

Oral steroids
Azathioprine
Ciclosporin
Methotrexate
Mycophenolate mofetil

Question 22

what risks are associated with immunosuppressants?

Answer 22

Risk of malignancy and serious infection

Need regular blood test monitoring, in particular
FBC (esp in methotrexate and azathioprine)
Renal function (esp ciclosporin)
Liver function (esp methotrexate)

Question 23

what are biologics?

Answer 23

The 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

Question 24

how are biologics named?

Answer 24

A series of infixes which immediately precede –mab:
zu humanised
ix chimeric
u fully human
li-/-l- immunomodulator
E.g.adalimumab = immunomodulator fully human monoclonal antibodies
Infliximab = immunomodulator chimeric monoclonal antibodies

Question 25

Current licensed biologics for dermatology conditions?

Answer 25

Psoriasis – nine
Hidradenitis suppurativa – one
Chronic spontaneous urticaria – one
Atopic eczema – one
Pemphigus – one

Question 26

what risks are associated with biologics?

Answer 26

Risk of infection
TB reactivation
Serious infection
Avoid live vaccines
Risk of malignancy
TNF inhibitors – risk of demyelination

Question 27

what targeted treatments are used for melanoma?

Answer 27

A revolution in treatment options for advanced melanoma
Targeted treatment for stage 4 disease
Adjuvant use in stage 3 disease

Targeted treatment
If BRAF 600 mutation
Vemurafenib
Dabrafenib
Immunotherapies
Ipilumumab
Pembrolizumab