Apremilast (brand name Otezla) is a pill for plaque psoriasis and psoriatic arthritis. It calms inflammation from the inside and does not need routine blood-test monitoring.
Finasteride is a pill that blocks the enzyme converting testosterone into DHT, the hormone that shrinks hair follicles. It's mainly a men's treatment, but is used off-label in some women — usually postmenopausal.
Isotretinoin, still widely known as Accutane, is the most powerful acne treatment available. It shrinks oil glands and, for most people, clears severe acne for good. It requires strict monitoring and cannot be taken during pregnancy.
Methotrexate is a pill (or shot) that calms an overactive immune system. Doctors use it for moderate to severe psoriasis and for psoriatic arthritis.
Oral antihistamines are pills that calm allergic reactions. They are the main first-line treatment for hives (itchy welts on the skin).
Low-dose oral minoxidil is a pill version of Rogaine. It's used off-label for hair loss and is often more effective — and far easier to stick with — than the topical, because there's no daily scalp application.
Oral tranexamic acid is a clotting medication used off-label for melasma. It's one of the few treatments that addresses the blood-vessel side of melasma — a piece of the problem most brighteners ignore.
Spironolactone is a pill that blocks androgens (male hormones). Originally a heart medication, it's now widely used off-label in women for hormonal acne, hair loss, and unwanted facial hair.