According to an analysis of available research and pooled data, there is "good evidence" that medications to treat attention deficit hyperactivity disorder, or ADHD, may also be effective in treating key aspects of Alzheimer’s disease. This was published online by the Journal of Neurology Neurosurgery
The researchers believe that clinical trials with noradrenergic drugs including antidepressants, drugs to treat high blood pressure, and ADHD are warranted.
Noradrenergic drugs target noradrenaline (also known as norepinephrine), which is released from a network specialized noradrenergic neuron. This network is crucial for arousal as well as many cognitive processes such attention, learning, memory and preparing for action.
Noradrenergic alteration is seen in the initial stages of Alzheimer's disease. It contributes to cognitive and neuropsychiatric symptoms. This suggests that pharmacological treatment could be directed at the noradrenergic system.
The researchers looked for clinical trials that had been published in the 1980s and 2021 and in which noradrenergic medications, such as atomoxetine and methylphenidate and guanfacine were used to improve cognitive and/or psychopsychiatric symptoms in patients with neurodegenerative disorders.
There were 19 random controlled trials that focused on Alzheimer's disease or mild cognitive impairment. Six of them were rated as good, seven as fair, and six as poor. .
Results from 10 of these trials, involving 1,300 patients, were pooled for global cognition -- orientation/attention, memory, verbal fluency, language, and visuospatial ability. The Mini-Mental State Exam and the Alzheimer's Disease Assessment Scale showed that there was a significant positive effect of noradrenergic medications on global cognition.
Eight clinical trials involving 425 subjects were analyzed for their behavior, neuropsychiatric symptoms and agitation. This showed that noradrenergic drugs had a significant positive effect on apathy even after accounting for outliers and differences in trial design.
Researchers state that "repurposing existing noradrenergic drug is very likely to offer an efficient treatment for Alzheimer's disease general cognition and apathy."
They also stated that there are compelling reasons for more clinical trials of noradrenergic therapies in Alzheimer's disease.
They warn that there are many factors to consider. They recommend that patients be selected carefully and that they understand the interactions between drugs and other treatments. This will help minimize any potential side effects and maximize the benefits of noradrenergic drug.