Antiacne Medications

Antiacne Medications - Pimple Plot Points

• Acne Pathogenesis: Four key factors:
  • Follicular epidermal hyperproliferation → comedone formation.
  • Excess sebum production (androgen influence).
  • Cutibacterium acnes proliferation within follicles.
  • Inflammation due to bacterial products & altered sebum.
• Therapeutic Targets:
  • Keratolytics: Salicylic acid, retinoids.
  • Sebostatics: Isotretinoin, hormonal therapies.
  • Antimicrobials: Benzoyl peroxide, antibiotics (topical/oral).
  • Anti-inflammatories: Corticosteroids (limited use), NSAIDs (adjunctive).

⭐ Isotretinoin (oral retinoid) is highly effective for severe nodulocystic acne but is a potent teratogen, mandating strict contraception during and after therapy (e.g., iPLEDGE program).

Antiacne Medications - Surface Level Warfare

• Key Targets: ↓ Sebum, ↓ P. acnes, ↓ inflammation, normalize keratinization.

• Topical Retinoids (Adapalene, Tretinoin): Normalize keratinization, comedolytic. S/E: Irritation, photosensitivity. Adapalene gentler.
• Benzoyl Peroxide (BPO): Antibacterial (no resistance!), keratolytic. S/E: Bleaching, irritation. Often combined.
• Topical Antibiotics (Clindamycin): ↓ P. acnes. Use with BPO to ↓ resistance.
• Oral Antibiotics (Doxycycline, Minocycline): Moderate-severe acne. Anti-inflammatory. Limit use (3-6 months). Doxy: photosensitivity.
• Oral Isotretinoin: Severe/recalcitrant acne. MOA: Hits all 4 pathogenic factors. ⚠️ Teratogenic (iPLEDGE). S/E: Dryness, ↑LFTs/lipids. Dose: 0.5-1 mg/kg/day. Cumulative: 120-150 mg/kg.

⭐ Isotretinoin is the only drug targeting all four major pathogenic factors of acne.

Antiacne Medications - Systemic Inside Jobs

• Systemic Antibiotics: For moderate-severe inflammatory acne. Target P. acnes, ↓inflammation.
  • Tetracyclines (First-line):
    • Doxycycline: 100-200 mg/day. Photosensitivity. Avoid pregnancy, <8 yrs.
    • Minocycline: 50-100 mg/day. Vestibular toxicity, pigmentation.
    • Lymecycline: 300 mg/day. Good efficacy, better GI tolerance.
  • Macrolides: (Erythromycin, Azithromycin) - Alternative. ↑Resistance concern.
• Hormonal Therapy (Females): For persistent acne, hyperandrogenism signs (PCOS).
  • Combined Oral Contraceptives (COCs): ↓Ovarian androgens, ↑SHBG → ↓free testosterone, ↓sebum.
    • E.g., Ethinylestradiol + Drospirenone / Cyproterone acetate.
  • Spironolactone: Antiandrogen. Dose: 25-200 mg/day.
    • ⚠️ Monitor K+. Side effects: Menstrual irregularities, breast tenderness.

⭐ Minocycline is known for causing blue-black pigmentation, especially in acne scars, and can also lead to drug-induced lupus.

Antiacne Medications - Isotretinoin's Reign

• Isotretinoin (13-cis-retinoic acid): Oral retinoid for severe, recalcitrant nodulocystic acne.
  • Mechanism: ↓ sebum, ↓ P. acnes, ↓ inflammation, normalizes keratinization.
  • Dose: 0.5-1 mg/kg/day for 16-24 weeks. Cumulative dose 120-150 mg/kg.
  • ⚠️ Teratogenicity: Absolute contraindication in pregnancy (iPLEDGE program). Two forms of contraception mandatory.
  • Key Side Effects:
    • Mucocutaneous: Cheilitis (most common), dry skin, epistaxis.
    • Systemic: Hypertriglyceridemia, ↑ LFTs, myalgia.
    • Rare: Pseudotumor cerebri (avoid concurrent tetracyclines), depression.
  • Monitoring: LFTs, lipids (baseline, monthly). Pregnancy tests (before, during, after therapy).

⭐ Isotretinoin is the only acne medication that affects all four major pathogenic factors of acne.

High‑Yield Points - ⚡ Biggest Takeaways

• Topical retinoids (e.g., adapalene): first-line for comedonal acne; normalize keratinization.
• Benzoyl peroxide: potent bactericidal (vs. P. acnes), keratolytic; no bacterial resistance.
• Topical antibiotics (clindamycin): for inflammatory acne; combine with benzoyl peroxide to reduce resistance.
• Oral tetracyclines (doxycycline): for moderate-to-severe inflammatory acne.
• Oral isotretinoin: for severe, recalcitrant acne; highly teratogenic (strict pregnancy prevention).
• Azelaic acid: antibacterial, anti-inflammatory, comedolytic; targets post-inflammatory hyperpigmentation.
• Hormonal therapy (OCPs, spironolactone): for female acne with hyperandrogenism signs.