Systemic therapy refers to acne medication that is taken by mouth. Antibiotics like tetracycline, minocycline, doxycycline, or erythromycin may treat moderate to severe acne by targeting bacteria and reducing inflammation. Other systemic therapies include oral contraceptives, which can reduce acne in some women, spironolactone, an anti-androgen hormone pill, and isotretinoin (high-dose prescription vitamin A). Isotretinoin is used only in certain severe, cystic acne cases, or in cases where other treatments don't work. A course of isotretinoin treatment requires regular appointments with your dermatologist.