Lecture Notes: Dermatology and Pharmacology

Introduction

• Dicloxacillin

  • Anti-staphylococcal penicillin.
  • Primarily used for MSSA (Methicillin-Sensitive Staphylococcus Aureus).
  • Used when cultures show MSSA, after initially treating with broader-spectrum antibiotics like vancomycin.
  • Benefits include a narrow spectrum that reduces other bacterial resistance.

• Stream Quality

  • Improvements made to stream quality.
  • No drop frames, indicating stable stream.

Dermatologic Pharmacology

Drug Penetration and Absorption

• Variability in response due to skin thickness.
• Thin areas allow more drug to permeate (e.g., scrotum, face).
• Systemic effects possible with drugs like estrogen or fentanyl patches.
• Concentration gradient affects absorption; higher doses can overcome resistance.
• Skin can act as a drug reservoir.

Dermatologic Vehicles

• Types: Creams, ointments, gels, lotions, tinctures.
• Occlusion: More occlusive vehicles like ointments keep drugs on skin longer.
• Drug Solubility: Depends on vehicle's ability to dissolve the drug.
• Stability: Vehicles with water may need preservatives to prevent bacterial growth.
• Therapeutic Effects: Vehicles may aid in drying or moistening the skin.

Acne Treatment

• Pathogenesis: Involves increased sebum, keratinization, bacterial growth, and inflammation.
  • Stress can exacerbate due to increased cortisol.
• Drug-Induced Acne: Corticosteroids, antiepileptics, lithium, and others.

Therapies

• Non-Pharmacologic: Cleanliness, lukewarm baths, avoid irritants.

• Topical Treatments:

  • Benzoyl Peroxide: Antibacterial, comedolytic.
  • Azelaic Acid: Antibacterial, reduces testosterone conversion.
  • Topical Retinoids: Correct abnormal follicular keratinization, reduce P. acnes.
  • Topical Antibiotics: Clindamycin, erythromycin.

• Systemic Treatments:

  • Isotretinoin (Accutane): Severe side effects, REMS program for teratogenic risk.
  • Systemic Antibiotics: Tetracyclines.

Specific Conditions

• Atopic Dermatitis: Eczema, chronic inflammation.
  • Use of topical steroids (low, medium, high potency based on severity).
  • Steroid Potency Factors: Drug type, concentration, salt form, vehicle.

Other Dermatologic Agents

Topical Antibiotics

• Bacitracin: Broad range, not systemically absorbed.
• Mupiricin: Effective against MRSA.
• Polymyxin B: Gram-negative coverage.

Topical Antifungals

• Azoles: Clotrimazole, ketoconazole.
• Terbinafine, Naftifine: For tinea infections.
• Nystatin: For candida infections like diaper rash.

Topical Antivirals

• Acyclovir, Pencyclovir: For herpes simplex virus.

Immunomodulators

• Tacrolimus, Pimecrolimus: For patients intolerant to steroids.

Conclusion

• Effective stream session.
• Next session on Autonomic Nervous System.

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Note: This lecture covered a variety of dermatology-related pharmacological treatments and considerations, focusing on both the mechanisms of action and practical applications of various topical and systemic medications.