Dihydrexidine

Dihydrexidine (DAR-0100) is a moderately selective full agonist at the dopamine D₁ and D₅ receptors. It has approximately 10-fold selectivity for D₁ and D₅ over the D₂ receptor. Although dihydrexidine has some affinity for the D₂ receptor, it has functionally selective D₁ signaling, thereby explaining why it lacks D₂ agonist behavioral qualities.

Dihydrexidine has shown impressive antiparkinson effects in the MPTP-primate model, and has been investigated for the treatment of Parkinson's disease. In an early clinical trial the drug was given intravenously and led to profound hypotension so development was halted. The drug was resurrected when it was shown that smaller subcutaneous doses were safe. This led to a pilot study in schizophrenia and current clinical trials to assess its efficacy in improving the cognitive and working memory deficits in schizophrenia and schizotypal disorder.

There have been several reviews of relevance to the compound.