Benzoyl peroxide/clindamycin  Benzoyl peroxide/clindamycin is a topical gel used for the treatment of acne. It is a combination of clindamycin, an antibiotic, and benzoyl peroxide, an antiseptic. All formulations are prescription drugs. Common side effects include peeling, itching, and dryness of the skin where the gel was applied. The gel is used on the skin to treat light to medium acne vulgaris in people 12 years and older. BenzaClin is to be applied twice daily, and Duac and Onexton are once-a-day medications. Continued use beyond 12-weeks has not been studied. There is an average 52% decrease in inflammatory acne lesions by week 12. The combination less is effective than benzoyl peroxide/salicylic acid after short-term treatment of two to four weeks, but the two treatments showed similar effectiveness after ten to twelve weeks. Currently, studies on whether or not the use of benzoyl peroxide/clindamycin gels is teratogenic or has adverse effects on nursing infants has not been performed. While oral clindamycin passes into breast milk, no such data are available for clindamyin in gel form. Limited data regarding topical benzoyl peroxide and clindamycin have shown no safety problems. The gel is not recommended for those who are allergic to clindamycin, benzoyl peroxide, any components of the formulation, or lincomycin. Individuals previously diagnosed with regional enteritis, ulcerative colitis, or antibiotic-associated colitis are also recommended not to use it. Common side effects are peeling, itching, redness, dryness, burning, and dermatitis. Benzoyl peroxide bleaches hair, clothes, towels, bedclothing, and the like. Prolonged exposure to natural or artificial sun light (UV rays) is not recommended because the gel may cause photosensitivity. Irritation due to benzoyl peroxide can be reduced by avoiding harsh facial cleansers and wearing sunscreen prior to sun exposure. Clinical studies have shown systemic absorption of clindamycin through topical application, in some cases leading to diarrhea, bloody diarrhea, and colitis. Reports of anaphylaxis were also seen. However, the sources of these reports were personal accounts without controls and of an unknown population, thus it is difficult to attribute their cause to the benzoyl peroxide/clindamycin gel.