Clindamycin + Nicotinamide is a combination of two medicines: Clindamycin and Nicotinamide, which treats pimples (acne). Clindamycin is an antibiotic which works by penetrating into the skin and killing acne-causing bacteria. Nicotinamide is a form of vitamin B. It exerts anti-inflammatory effects when applied to the skin and reduces swelling, redness and tenderness associated with acne.