Pharm

Tretinoin

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Tretinoin, Retin A, Retin-A, Retinoid

  • Definitions
  1. Retinoids
    1. Retinoids are Vitamin A derived compounds
    2. Retinoic Acid occurs naturally in humans and is involved in cell development and growth (esp. Embryo)
  • 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
  • Preparations
  • Tretinoin
  1. Standard preparations
    1. Retin A Cream 0.025% 0.05% 0.1%
      1. Cream 0.025% is as effective and less irritating than .05-.1%
      2. Lower concentration simply takes a little longer for improvement
    2. Retin A Gel 0.01%, 0.025% 0.005%
    3. Retin A Lotion 0.05% (Avoid - VERY irritating)
      1. Altreno (0.05% lotion)
        1. Released in 2019 as "hydrating" with collagen and hyaluronic acid
        2. Contains fish proteins (risk of Allergic Reaction)
        3. Expensive ($120/45 grams) and unlikely to be covered by insurance
        4. No evidence of benefit over generic options (e.g. Tretinoin, Adapalene)
        5. (2019) Presc Lett 26(3): 16
  2. Less irritating agents
    1. Retin-A Micro (Tretinoin gel microsphere)
    2. Avita (Tretinoin 0.025%)
  • Preparations
  • Other Retinoids
  1. Topical Retinoids
    1. Adapalene (Differin)
    2. Tazarotene (Tazorac)
      1. More effective than either Adapalene or Tretinoin, but also more irritating
  2. Systemic Retinoids
    1. Isotretinoin (Accutane)
  • Dosing
  • Directions for use
  1. Apply one dot (split-pea size) per one triangle of face (forehead, right malar, left malar)
  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. Avoid use at same time as Benzoyl Peroxide (aside from microspore Tretinoin preparation)
    1. Tretinoin when combined with benyzoyl peroxide, results in oxidation and Tretinoin degradation
  • 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
  • Safety
  1. Pregnancy Category C
  • Efficacy
  1. Most potent Comedolytic
  2. Good results in 75% of patients in 3 months