III. 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)

IV. Mechanism

  1. Comedolytic
  2. Antiinflammatory activity
  3. Decreases sebum production
  4. Lowers cohesiveness of follicular epithelial cells
    1. Decreases micro-comedo formation
  5. Increases follicular cell turnover and normalizes epithelial cell Desquamation
    1. Results in extrusion of existing comedones

V. 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%)
  3. Combination agents
    1. Tretinoin 0.025% and Clindamycin 1.2% gel (Veltin, Ziana)
    2. Tretinoin 0.1% and Benzoyl Peroxide 3% cream (Twyneo)
      1. Formulated to prevent Benzoyl Peroxide from breaking down Tretinoin
      2. Applied once daily
      3. Available as a 30 g pump at $425 in 2022 (more than 10 fold the cost of the generic ingredients)
      4. (2022) Med Lett Drugs Ther 64(1650): 75 [PubMed]

VI. Preparations: Other Retinoids

  1. Topical Retinoids
    1. Adapalene (Differin)
      1. Also available as combination with Benzoyl Peroxide (Epiduo)
    2. Tazarotene (Tazorac)
      1. More effective than either Adapalene or Tretinoin, but also more irritating
  2. Systemic Retinoids
    1. Isotretinoin (Accutane)

VII. Dosing: Directions for use

  1. Apply one dot (split-pea size) per one triangle of face (forehead, right malar, left malar)
    1. Typically applied at night to reduce daytime photosensitivity and irritation
  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 at spaced intervals (e.g. Benzoyl Peroxide, Clindamycin)
    1. Clindamycin also reduces irritating effect of Tretinoin
    2. Example schedule
      1. Morning: Clindamycin or Benzoyl Peroxide 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

VIII. 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

IX. Safety

  1. Pregnancy Category C

X. Efficacy

  1. Most potent Comedolytic
  2. Good results in 75% of patients in 3 months

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Related Studies

Cost: Medications

tretinoin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
TRETINOIN 0.01% GEL Generic $3.53 per gram
TRETINOIN 0.025% CREAM Generic $1.24 per gram
TRETINOIN 0.025% GEL Generic $3.48 per gram
TRETINOIN 0.05% CREAM Generic $1.87 per gram
TRETINOIN 0.05% GEL Generic $4.26 per gram
TRETINOIN 0.1% CREAM Generic $2.53 per gram
TRETINOIN GEL MICRO 0.04% TUBE Generic $7.32 per gram
TRETINOIN GEL MICRO 0.1% TUBE Generic $8.85 per gram
retin-a (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
RETIN-A 0.01% GEL Generic $2.55 per gram
RETIN-A 0.025% CREAM Generic $1.24 per gram
RETIN-A 0.05% CREAM Generic $1.87 per gram
RETIN-A 0.1% CREAM Generic $2.40 per gram
altreno (on 8/17/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
ALTRENO 0.05% LOTION $2.45 per gram