You are so, so , so wrong. Why do you thing that all tetracyclines are using on Acne !! ACNE is not a bacterial problem, no any other antibiotic works. READ PUBMED ! read clinical trial, read studies. Damn, is not so hard .
If you think that doxy or mino still kill bacteria, do a little research, this drugs have being on the market since early 70s , have you ever heard about resistance ?
If is an bacterial problem, can you please explain why Finasteride, dutasteride, spironolactone, works in acne ?