MRZ-9547, also known as (R)-phenylpiracetam, (R)-phenotropil, or (R)-fonturacetam, is a selective dopamine reuptake inhibitor ( = 14.5üM) that was developed by Merz Pharma. It is the (R)-enantiomer of the racetam and nootropic phenylpiracetam (phenotropil; fonturacetam).
The drug was under development for the treatment of fatigue associated with Parkinson's disease and was in phase 1 clinical trials for this indication in June 2014. However, no recent development has been reported as of November 2017. There was also interest in MRZ-9547 for treatment of fatigue in people with depression and other conditions, but this was not pursued.
Similarly to other dopamine reuptake inhibitors and related agents, MRZ-9547 has been found to have pro-motivational effects in animals and to reverse motivational deficits induced by the dopamine depleting agent tetrabenazine.
The drug, as the enantiopure (R)-enantiomer of phenylpiracetam, was first described in the scientific literature by 2014.