Droxidopa

Droxidopa (L-DOPS) is a synthetic precursor and prodrug of the neurotransmitter norepinephrine.¹ It is transformed into norepinephrine through the action of DOPA decarboxylase. L-DOPS increases norepinephrine levels in the rat heart following intraperitoneal administration and in the brain following intracerebroventricular administration at doses of 125 and 100 µg/animal, respectively. It increases arterial pressure and mesenteric arterial resistance in rats with ligated portal vein or biliary ducts when used at doses of 25-50 mg/kg.² L-DOPS crosses the blood brain barrier, however, its effects can be blocked by the peripherally-restricted DOPA decarboxylase inhibitor carbidopa (Item No. 23783), indicating that the mechanism is peripheral.^3,2 Formulations containing droxidopa are used in the treatment of neurogenic orthostatic hypotension.

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1. Bartholini, G., Constantinidis, J., Puig, M., et al. The stereoisomers of 3,4-dihydroxyphenylserine as precursors of norepinephrine. J. Pharmacol. Exp. Ther. 193(2), 523-532 (1975).

2. Coll, M., Rodriguez, S., Raurell, I., et al. Droxidopa, an oral norepinephrine precursor, improves hemodynamic and renal alterations of portal hypertensive rats. Hepatology 56(5), 1849-1860 (2012).

3. Kaufmann, H., Norcliffe-Kaufmann, L., and Palma, J.-A. Droxidopa in neurogenic orthostatic hypotension. Exp. Rev. Cardiovasc. Ther. 13(8), 875-891 (2015).