Atomoxetine Drug Properties for Repurposing as a Candidate Alzheimer's Disease Therapeutic Agent

Ongoing Alzheimer's disease (AD) drug development research addresses the need for therapeutic agents that can ameliorate cognitive symptoms and attenuate the course of AD synaptic deficits and neurodegeneration. There is growing interest in evaluating FDA-approved drugs for repurposing as candidate AD therapeutics. Such drugs have the advantage that data are available about their pharmaceutical properties, including doses, pharmacokinetics, pharmacodynamics, biomarkers, metabolism, and safety, to inform the design of clinical drug trials. Importantly, the suitability of such drugs with properties needed for AD requires evaluation. In the early stage of AD, degeneration of the locus coeruleus (LC) brain region results in the reduction of noradrenergic neurons and the loss of the neurotransmitter norepinephrine (NE) that regulates cognition and degeneration. Elevation of extracellular NE through inhibition of the NE transporter (NET) is hypothesized to ameliorate AD deficits. Notably, the NET reuptake inhibitor atomoxetine, an FDA-approved drug for the treatment of attention deficit hyperactivity disorder (ADHD), provides an attractive candidate as an AD therapeutic agent because it may attenuate cognitive decline in AD patients, positively impact AD biomarkers, and reduce neuropathology. The goal of this review is to assess atomoxetine for repurposing in AD based on its ability to improve cognition, regulate NE, impact AD biomarkers, and preserve LC neuronal function, with suitable pharmacokinetics, drug metabolism, and safety based on analysis of clinical and preclinical studies. Evidence for neuroprotective effects of atomoxetine in the early stage of AD at clinically safe doses with suitable pharmaceutical properties supports its candidacy as a repurposed drug for AD therapeutics.