Fipamezole is a new antagonist of the pre-synaptic adrenergic alpha-2 receptors and is being investigated for potential use as an adjunctive therapy for PD. Adrenergic alpha-2 receptors inhibit noradrenaline and some other neurotransmitter release from nerve terminals in a tonic manner, and therefore antagonism of this receptor leads in enhanced neurotransmitter release. Alpha-2 receptors are located widely in the body, both in the central nervous system (CNS) and periphery. Pharmacological studies have suggested that either central or peripheral autonomic nervous system is involved in autonomic failure and orthostatic hypotension in MSA and in PD. Neurogenic orthostatic hypotension in these diseases results from decreased delivery of the sympathetic neurotransmitter noradrenaline (or hormonal adrenaline) to vascular adrenergic receptors, either because of blunted CNS control or impaired function of postganglionic sympathetic neurons. Fipamezole is expected to increase noradrenergic (or adrenergic) turnover in specific areas of the brain or in the periphery in MSA and PD and alleviate symptoms related to fall in BP during orthostatism.