My dermatologist recommended tranexamic acid orally for melasma

if transexamic acid was very successful it would be a regular treatment offered by everyone and be a more regular treatment in the community.
Hyperpigmentation from any type needs a combination approach of peels like cosmelan,  lasers like clear and brilliant and aerolase or laser genesis, radiofrequency like venus viva, and constant skin care and sun protection.  Bimontly facials with silk peel dermalinfusion is essential to hydrate, exfoliate and infuse vitamins and antioxidants into the skin.  If you have acne you can do additional treatments and peels to get more improvement.  I suggest a formal consultation with an expert in lasers and peels. Best, Dr. Emer.

The short answer to your question is that both topical and oral tranexamic acid have relatively recently been found useful for fading melasma. Tranexamic acid, an FDA approved medication, has been used safely for quite some time to reduce excessive bleeding from a variety of causes.  Its successful use, both via topical and oral routes, for the treatment of melasma is more recent. Individuals with a higher risk for the developing of blood clots, such as smokers and those on birth control pills, need to be monitored carefully when taking this medication orally. Make sure you consult with a board certified aesthetic dermatologist. Best of luck to you. 

Dear ver212,
I would have to examine you but Melasma can be treated with a comprehensive approach.  Stopping or changing the birth control medication, avoidance of UV and direct light, and also retinol and hydroquinone treatment. You should always use sunscreen.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery