Benzoyl Peroxide (BPO) 2.5% w/w is a topical antimicrobial and keratolytic agent, considered a first-line treatment for mild to moderate inflammatory acne vulgaris. It is a stable, white crystalline powder formulated into creams, gels, and washes. In the Indian context, it is widely available as an over-the-counter (OTC) product, making it a cornerstone of acne management due to its efficacy, low cost, and favorable safety profile when used appropriately. It works by delivering oxygen into the pilosebaceous unit, creating an environment hostile to *Cutibacterium acnes* (formerly *Propionibacterium acnes*).
Adult: Apply a thin layer to affected areas once daily, preferably in the evening. Frequency may be increased to twice daily (morning and evening) as tolerated after 1-2 weeks.
Note: 1. Wash hands and gently cleanse the affected area with a mild soap/cleanser. Pat dry. 2. Apply a pea-sized amount for the entire face or a thin layer to each lesion. 3. Avoid contact with eyes, eyelids, lips, mouth, nostrils, and mucous membranes. 4. May bleach colored fabrics, hair, and bedding. Allow to dry completely before contact with such materials.
Benzoyl Peroxide exerts its anti-acne effects through three primary mechanisms: 1) **Antimicrobial Action:** It is a potent oxidizing agent that releases free oxygen radicals upon contact with the skin. These radicals oxidize proteins in *Cutibacterium acnes*, leading to bacterial cell death. It reduces both surface and follicular bacterial counts. 2) **Keratolytic & Comedolytic Action:** It promotes desquamation of the stratum corneum and increases turnover of follicular epithelial cells, helping to unplug existing comedones (blackheads and whiteheads) and prevent the formation of new ones. 3) **Anti-inflammatory Action:** By reducing the population of *C. acnes*, it decreases the production of pro-inflammatory chemotactic factors and hydrolytic enzymes that contribute to inflammation and pustule formation.
Pregnancy: US FDA Pregnancy Category C. Animal reproduction studies have not been conducted. No adequate and well-controlled studies in pregnant women. Use only if clearly needed and potential benefit justifies potential risk to the fetus. Minimal systemic absorption reduces risk.
Driving: No effect.
| Topical Tretinoin/Retinoids | Concurrent use may increase skin irritation and degradation of tretinoin. It is recommended to apply them at different times of the day (e.g., BPO at night, tretinoin in the morning or alternate nights). | Moderate |
| Topical Sulfur, Resorcinol, Salicylic Acid | Increased risk of excessive skin dryness and irritation. | Moderate |
| Photosensitizing Drugs (e.g., Tetracyclines, Fluoroquinolones) | BPO may increase photosensitivity. Caution advised with sun exposure. | Low |
| Aminolevulinic Acid (for photodynamic therapy) | BPO may inactivate aminolevulinic acid. Discontinue BPO prior to PDT. | Major |
Same composition (Benzoyl Peroxide (2.5% w/w)), different brands: