Tranexamic acid (trans-4-aminomethylcyclohexanecarboxylic
acid; TXA; a synthetic lysine analog which has an antifibrinolytic effect
through the reversible blockade of lysine-binding sites on plasminogen
molecules) is a procoagulant agent that is FDA-approved for treatment of
menorrhagia and to prevent hemorrhage in patients with hemophilia undergoing
tooth extractions. Tranexamic acid
exerts effects on pigmentation via its inhibitory effects on UV light-induced
plasminogen activator and plasmin activity (UV radiation induces plasminogen
activator synthesis and increases plasmin activity in keratinocytes, which stimulates the
release of arachidonic acid via phospholipase A2. Free arachidonic acid
stimulates melanogenesis via its metabolite, prostaglandin E2. Increased
plasmin itself elevates α-melanocyte-stimulating hormone, which activates
melanin synthesis in melanocyte. Plasmin also plays a role in the release of
basic fibroblast growth factor [FGF], which is again a potent melanocyte growth
factor. All of these processes result in more melanin production in the skin). Methods of TXA administration
in melasma (as a single or adjuvant treatment) include oral tabs (250 mg twice daily for ±3
months; a safe therapeutic option, easy to administer with few and mild side
effects; e.g. heartburn, nausea, abdominal pain, and epigastric discomfort), topical
(2% emulsion, 3% cream & 5% solution), intradermal injection in the
concentration of 4mg/mL, and in combination with microneedling.
