Pharmacology of fusaric acid in man

Fusaric acid (5‐butylpicolinic acid) is shown to be an effective, partially reversible inhibitor of human plasma dopamine‐β‐hydroxylase (DBH), clinically reducing mean arterial blood pressure, in a dose range of 300 to 600 mg per day. Maximum inhibition of plasma DBH activity occurs 2.5 hours after oral administration. The biological half‐life of fusaric acid in blood is approximately 12 hours. A fusaric acid concentration of 23 ng per milliliter produces 50% inhibition of plasma DBH activity in vitro. It is suggested that the degree of plasma DBH inhibition by fusaric acid may be used for estimates of fusaric acid blood levels.