Droxidopa for ADHD

Droxidopa (L-threo-dihydroxyphenylserine, L-DOPS) is a prodrug of dopamine and noradrenaline. It can cross the blood-brain barrier and is converted to dopamine and noradrenaline in the brain.

USA: Northera (since 2014)
Japan: DOPS (since 1989)
Switzerland: no approval to date

Droxidopa is considered an orphan drug.

A combination of droxidopa and benserazide, a peripheral amino acid decarboxylase inhibitor, had a stimulating effect on the PFC and inhibited dopaminergic neurons in rats. Further, in juvenile SHR/NCrl rats, which serve as an animal model of ADHD-C:¹

• Hyperactivity reduced
• Impulsiveness reduced
• Inattention reduced

In juvenile WKY/NCrl rats, which serve as an animal model of ADHD-I subtype, administration of droxidopa with benserazide induced:¹

• Impulsiveness reduced
• Inattention unchanged

Its use in the treatment of ADHD in humans has hardly been researched to date.
A small open study with Droxidopa (3 x day 200 to 600 mg over 3 weeks) found an improvement in ADHD symptoms without significant side effects. Nevertheless, 7 of the 20 participants terminated their participation prematurely.²