Biacna is a topical gel used to treat acne vulgaris which is characterized by comedones, inflammatory papules or pustules, with or without the presence of occasional nodules. It is not used for the treatment of other acne varieties like pustular and deep cystic nodular acne. The active ingredients in Biacna are clindamycin phosphate (a lincosamide antibiotic) and tretinoin (a retinoid).