Hydroquinone

Category: topical

Pharmacological Mechanism

Tyrosinase inhibitor — blocks melanin synthesis in melanocytes. Topical 2% (OTC in some countries) and 4% (Rx) for melasma + post-inflammatory hyperpigmentation. Long-term high-strength use risks ochronosis (paradoxical darkening) — typically cycled.

Half-Life (t½)

TD: 24h

Dosing Guidelines

• TD: Typical 4mg (Range: 2 - 4 mg)

Target Organ Systems

• integumentary
• immune-hematologic