Nepicastat (SYN-117) HCl is primarily investigated for its potential in treating conditions related to the central nervous system. It acts as a selective inhibitor of dopamine β-hydroxylase, an enzyme involved in the conversion of dopamine to norepinephrine. By inhibiting this enzyme, it increases dopamine levels and decreases norepinephrine, helping to regulate neurotransmitter balance. This makes it a candidate for addressing stress-related disorders, such as post-traumatic stress disorder (PTSD). Research has shown its potential to reduce symptoms like anxiety and fear memory retention in preclinical studies. Additionally, it is being explored for its role in managing cardiovascular conditions, as it may influence sympathetic nervous system activity. Furthermore, studies suggest its use in treating cocaine addiction by modulating the catecholamine system to aid in behavior control. Its applications highlight its dual therapeutic potential in neurological, cardiovascular, and addiction-related health.