This is a very scientific question . Well understanding of these antibiotic is necessary for substantial results in acne. Most of the antibiotic used in acne is for anti-inflammatory property and not the antibiotic property per se. Your dermatologist must have had a plan for prescribing the drugs to you. It depends on the presentation and suitability of the patient as to which drug will suit him/her better. These two belong to the same class but can vary widely in usage.