Droxidopa for ADHD
Droxidopa (L-threo-dihydroxyphenylserine, L-DOPS) is a prodrug of dopamine and norepinephrine. It can cross the blood-brain barrier and is converted to dopamine and norepinephrine in the brain.
USA: Northera (since 2014)
Japan: DOPS (since 1989)
Switzerland: no approval so far
Droxidopa is considered an orphan drug.
A combination of droxidopa and benserazide, a peripheral amino acid decarboxylase inhibitor, had a stimulatory 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, showed:1
- Hyperactivity reduced
- Impulsivity 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
- Impulsivity reduced
- Inattention unchanged
Its use in the treatment of ADHD in humans has hardly been researched to date.
A small open-label trial of droxidopa (200 to 600 mg 3 times a day for 3 weeks) found improvement in ADHD symptoms without significant side effects. Nevertheless, 7 of the 20 participants terminated participation prematurely.2
Dela Peña, Shen, Shi (2021): Droxidopa alters dopamine neuron and prefrontal cortex activity and improves attention-deficit/hyperactivity disorder-like behaviors in rats. Eur J Pharmacol. 2021 Feb 5;892:173826. doi: 10.1016/j.ejphar.2020.173826. PMID: 33347825. ↥ ↥
Adler, Gorny (2019): Pilot Study of Droxidopa With Carbidopa in Adults With ADHD. J Atten Disord. 2019 Jan;23(2):189-198. doi: 10.1177/1087054715580393. PMID: 25907673. n = 20 ↥