Duac Gel (Clindamycin/Benzoyl Peroxide): Uses, Application, Side Effects, and Interactions

Duac is a prescription topical gel combining clindamycin 1% (antibiotic) and benzoyl peroxide 5% (keratolytic/antibacterial) for acne vulgaris.

Mechanism

• Clindamycin: inhibits C. acnes protein synthesis.
• BPO: oxidizes bacterial proteins/lipids, comedolytic, prevents antibiotic resistance.

Usage

• Apply thin layer to clean, dry affected areas once daily at bedtime (some regimens bid).
• Pea-sized amount for full face.
• Avoid eyes, lips, mucous membranes.
• Wash hands after.

Side Effects

• Common: dryness, erythema, peeling, burning, stinging (usually transient).
• Photosensitivity → use sunscreen.
• Contact dermatitis (allergic).
• Rare: severe colitis (clindamycin systemic absorption).

Interactions

• Other topicals: avoid concurrent irritants (retinoids, salicylic acid, glycolic acid) or stagger (AM/PM).
• Oral erythromycin (antagonism).
• Neuromuscular blockers (clindamycin potentiates).

Storage

Room temperature, avoid freezing/heat. Discard after expiration.