Lecture 3: Dermatology Pharmacology and Prescribing

Question 1

licensed medication is approved for use in the UK by either:

Answer 1

• MRHA: medicine and healthcare products regulatory agency
• EMA: european medicines agency

Question 2

list the causes of prescription errors

Answer 2

• lack of knowledge: about the patient, medication, allergies
• mistake writin/generating the prescription
• poor communication
• no local or national guidelines

Question 3

what does pharmacokinetics refer to?

Answer 3

• the effect of the body on the drug
• think about distribution, metabolism (especially in liver disease) and excretion (especially in renal disease)

Question 4

what does pharmacodynamics refer to?

Answer 4

• the effect of the drug on the body
• think about patient age, pregnancy risk, drug interactions, pharmacogenetics

Question 5

topical therapy includes a vehicle + active drug. What is a vehicle in this context?

Answer 5

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

Question 6

give examples of drugs used topically

Answer 6

• corticosteroid
• antibiotic
• antiviral
• dithranol
• vitamin analogues
  etc.

Question 7

how do topical steroids work?

Answer 7

anti-inflammatory and immunosuppressive properties:
- regulate pro-inflammatory cytokines
- suppress fibroblast, endothelial and leukocyte function
- vasoconstriction
- inhibit vascular permeability

Question 8

how much is a finger tip unit?

Answer 8

• about 0.5g
• should treat area double the size of one hand

Question 9

list the side effects of topical steroids

Answer 9

• skin thinning/atrophy
• stiae
• bruising
• hirsutism
• telangiectasia
• acne/rosacea, perioral dermatitis
• glaucoma
• systemic absorption
• cataracts

Question 10

give examples of systemic treatments used in dermatology

Answer 10

• retinoids
• traditional immunosuppressants
• biologics (also immunosuppressive)

Question 11

how do retinoids work?

Answer 11

vitamin A analogues:
- normalise keratinocyte function
- anti-inflammatory and anti-cancer effects

Question 12

which skin conditions are retinoids effective in treating? name the different retinoids prescribed for each

Answer 12

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

Question 13

retinoids CI and side effects

Answer 13

• teratogenic: careful patient selection
• chelitis (dry lips) and xerosis (dry skin)
• increase transaminases and triglycerides
• rarely psychiatric, eye, bone side effects

Question 14

list the immunosuppressants used in the treatment of inflammatory skin disorders

Answer 14

• oral steroids
• azathioprine
• ciclosporin
• methotrexate
• mycophenolate mofetil

Question 15

immunosuppressants disadvantages

Answer 15

• risk of malignancy and serious infection
• need regular blood test monitoring in particular:
• FBC esp. methotrexate and azathioprine
• renal function esp. ciclosporin
• liver function esp. methotrexate

Question 16

describe biologics used in dermatology and how do they work?

Answer 16

• the next gen 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 17

what does a biologic ending in ‘-cept’ indicate?

Answer 17

it is a receptor fusion
- Etanercept: genetically engineered fusion protein

Question 18

what does a biologic ending in ‘-mab’ indicate?

Answer 18

used to denote monoclonal antibodies

Question 19

biologics cause increased risk of?

Answer 19

• infection: TB reactivation, serious infection, avoid live vaccines
• malignancy
• TNF inhibitors: risk of demyelination

Question 20

what biologics are used for targeted treatment of stage 4 melanoma?

Answer 20

• if BRAF 600 mutation: Vemurafenib and Dabrafenib
• immunotherapies: Ipilumumab and Pembrolizumab