Tretinoin

Aka: Tretinoin, Retin A

1. Indications
   1. Acne Vulgaris
   2. Photodamaged skin
2. Available Preparations
   1. Cream 0.025% 0.05% 0.1%
      1. 0.025% as effective, less irritating than .05-.1%
      2. simply takes a little longer for improvement
   2. Gel 0.025% 0.01%
   3. Lotion 0.05% (Avoid - VERY irritating)
   4. Less irritating agents
      1. Retin-A Micro (Tretinoin gel microsphere)
      2. Avita (Tretinoin 0.025%)
3. Directions for use
   1. Apply one dot per one triangle of face
   2. Initially apply only for a few hours
      1. Slowly increase length of treatment
      2. Titrate up to overnight application as tolerated
   3. Often used with Topical Antibiotics (e.g. Clindamycin)
      1. Clindamycin reduces irritating effect of Tretinoin
      2. Example schedule
         1. Morning: Clindamycin applied
         2. Evening: Tretinoin applied
4. Adverse Effects
   1. Scaling
   2. Skin dryness
   3. Local irritation, erythema or inflammation
      1. Creams irritate less than lotions
      2. Irritation can be reduced by adding Hydrocortisone
         1. 1 part Retin A 0.025%, 1 part Hydrocortisone 1%
   4. Local skin sensation of burning or stinging
   5. Local Pruritus
   6. Photosensitivity
   7. Initially exacerbates inflammatory lesions
5. Efficacy
   1. Most potent Comedolytic
   2. Good results in 75% of patients in 3 months
6. Mechanism
   1. Comedolytic
   2. Lowers cohesiveness of follicular epithelial cells
      1. Decreases micro-comedo formation
   3. Increases follicular cell turnover
      1. Results in extrusion of existing comedones