DERMA

• What are the variables affecting pharmacologic response in dermatology?


  • Regional variation in drug penetration
  • Concentration gradient
  • Dosing schedule
  • Vehicles and occlusion
• Which areas of the body have the highest drug penetration?

  Axilla, face, scrotum, scalp
• How does the concentration gradient affect drug transfer?

  Increasing the concentration gradient increases the mass of drug transferred per unit time.
• Why can drugs with short half-lives be applied once daily?

  Because the skin acts as a reservoir for the drugs.
• What is the role of vehicles in dermatologic pharmacology?

  • Maximizes penetration of drug through skin
  • Provides moistening and drying effects
• What is occlusion in dermatologic pharmacology?

  Application of plastic wrap to hold the drug and its vehicle in close contact with the skin.
• What factors are important in vehicle selection for dermatologic applications?

  • Solubility of the active agent in the vehicle
  • Rate of release of the agent from the vehicle
  • Ability to hydrate the stratum corneum
  • Stability of the therapeutic agent in the vehicle
  • Interactions of the vehicle, stratum corneum, and active agent
• What are the different types of dermatologic formulations?

  • Tinctures
  • Wet dressings
  • Lotions
  • Gels
  • Powders
  • Pastes
  • Creams
  • Ointments
• Which dermatologic formulations are recommended for acute inflammation with oozing?

  Drying preparations such as tinctures, wet dressings, and lotions.
• What formulations are suitable for chronic inflammation with xerosis?

  Creams and ointments.
• What is the primary use of emulsifying agents in dermatologic formulations?

  To provide homogenous, stable preparations when mixing immiscible liquids.
• What are common adverse effects of dermatologic preparations?

  • Burning or stinging sensation
  • Drying and irritation
  • Pruritus
  • Erythema
  • Sensitization
  • Staining
  • Superficial erosion
• What are the types of local reactions to topical medications?

  • Irritation (Nonallergic)
  • Photoirritation (Nonallergic)
  • Allergic contact dermatitis (Allergic)
  • Photoallergic contact dermatitis (Allergic)
  • Immunologic contact urticaria (Allergic)
  • Nonimmunologic contact urticaria (Nonallergic)
• What is the mechanism of photoirritation?

  Phototoxicity; usually requires UVA exposure.
• What type of hypersensitivity is allergic contact dermatitis?

  Type IV delayed hypersensitivity.
• Which topical antibacterial agent is used for Gram (+) bacteria?

  Gramicidin.
• What is the total daily dose limit for topical antibacterial agents applied to denuded skin or open wounds?

  200 mg.
• What is the primary use of mupirocin?


  Treatment of impetigo caused by S. aureus and group A β-hemolytic streptococci.
• What is the form of bacitracin used in dermatology?

  Creams, ointments, and aerosol preparations.
• What is the mechanism of action of clindamycin?

  Inhibition of p-aminobenzoic acid utilization.
• What are the adverse local effects of metronidazole?

  Dryness, burning, and stinging.
• What is the primary use of azole derivatives in dermatology?

  To treat dermatophyte infections and candidiasis.
• What is the mechanism of action of fluconazole?

  Affecting the permeability of the fungal cell membrane through alteration of sterol synthesis.
• What is the recommended oral dosage for nystatin in treating oral candidiasis?

  Holding 5 mL of nystatin oral suspension in the mouth for several minutes 4 times daily before swallowing.
• What are the adverse effects of topical antifungal agents?

  • Stinging
  • Pruritus
  • Erythema
  • Local irritation
• What is the primary use of acyclovir?

  Treatment of recurrent orolabial HSV infection.
• What is the mechanism of action of imiquimod?

  Stimulates peripheral mononuclear cells to release interferon-α and stimulate macrophages.
• What are the common side effects of Tacrolimus and Pimecrolimus?

  • Burning sensation in the applied area
  • Improves with continued use
• What is the primary use of permethrin?

  Treatment of Pediculus humanus, Pthirus pubis, and Sarcoptes scabiei.
• What is the recommended application time for permethrin in treating scabies?

  Applied for the whole body for 8-14 hours.
• What are the agents affecting pigmentation in dermatology?

  • Hydroquinone
  • Monobenzone
  • Mequinol
  • Trioxsalen
  • Methoxsalen
• What is the mechanism of action of hydroquinone?

  Reduces hyperpigmentation by inhibiting the enzyme tyrosinase.
• What is the role of psoralens in dermatology?

  Used for the repigmentation of depigmented macules of vitiligo.
• What are the differences between sunscreens and sunshades?

  • Sunscreens absorb UV light (e.g., PABA, benzophenones)
  • Sunshades reflect light (e.g., titanium dioxide)
• What is the primary use of sunscreens?

  To absorb UV light.
• What conditions are sunscreens useful for?

  Polymorphous light eruption, lupus erythematosus, and drug reactions.
• What is hydroquinone used for?


  Topical application for skin whitening to reduce the color of skin
• What is a potential effect of monobenzone on melanocytes?

  It may be toxic, resulting in permanent depigmentation
• How do topical hydroquinone and mequinol affect skin pigmentation?

  They usually result in temporary lightening of the skin
• What enzyme do treatments for hyperpigmentation inhibit?

  Tyrosinase