Doxycycline
"In my teens, I had pretty bad acne. My doctor said it would clear up by 20. I'm now older and still am dealing with it. What has worked for me for the past ten years (with about two flareups a year) is: doxycycline 100mg twice a day (my plan is $5 for three months supply), Clearasil (10% benzoyl peroxide) tinted in the morning, and Metrogel (1% metronidazole gel) & Adult Acnomel (resorcinol) tinted in the evening. "