Tetracycline is a class of medications that includes the broad-spectrum antibiotic minocycline 100 mg. It functions by stopping the creation of bacterial proteins, which stops the germs that cause acne and skin infections from growing and spreading. Propionibacterium acnes, Streptococcus species, and Staphylococcus aureus are just a few of the many bacteria that minocycline is effective against.