Acne Vulgaris + Isotretinoin

Question 1

Method of action (MoA) of isotretinoin?

Answer 1

Vitamin A analogue - markedly reduces production of sebum

Question 2

How is acne vulgaris caused?

Answer 2

Increased sebum production

• blocked off hair follicles filled with sebum become comedones
• in these, Proprionibacterium acnes proliferate and induce an inflammatory response

Question 3

When is systemic isotretinoin indicated?

Answer 3

When

• other therapies have failed
• lesions are severe
• scarring is beginning to form
• patient is psychologically affected

Leads to complete clearance in 90% of patients

Question 4

What is a very common side effect of isotretinoin and what must be done?

Answer 4

Dry lips/other areas of the body
- patients must put up with it as much as they can as this is the mode of action of the drug (advise them not to use moisturiser)

Question 5

Other side effects of isotretinoin?

Answer 5

Highly teratogenic - females of reproductive age should be given contraception
Hyperlipidaemia
Raised LFTs
- should just be monitored as often resolve after termination of therapy
Some reports of increased incidence of depression but these are not consistently reproduced (patients should be warned to be vigilant but not that most people feel depressed)