Drug induced parkinsonism caused by the concurrent use of donepezil and risperidone in a patient with traumatic brain injuries

Acetylcholinesterase inhibitors to enhance recovery from traumatic brain injury: a comprehensive review and case series

OBJECTIVE

Acetylcholinesterase inhibitors (AChEIs) are used off-label, in both adult and pediatric patients, to help further neuro-recovery after traumatic brain injury (TBI). Evidence is limited and piecemeal. This review describes how TBI affects the cholinergic system and consolidates evidence supporting or refuting the use of AChEIs following TBI.

METHODS

NCBI MEDLINE search included all articles published through March 2021 on AChEI use in acute and post-acute adult TBI rehabilitation (treatment began <90 days or ≥90 days since injury, respectively), and in pediatric TBI rehabilitation. Further, we checked ClinicalTrials.gov for ongoing trials using AChEIs for TBI rehabilitation in the United States.

RESULTS

27 original articles from NCBI Medline, published through March 2021, were included. The use of AChEIs following TBI in acute and post-acute rehabilitation settings, in both adult and pediatric patients, along with medication side effects, is discussed.

CONCLUSIONS

Most studies showed benefits with only moderate effect sizes because of small sample sizes. Reported side effects are minimal and stop soon after AChEIs is discontinued. Conclusions are limited by paucity of research; but fortunately, a large randomized controlled trial is ongoing, and more are needed to truly determine the efficacy of AChEIs in helping with recovery from TBI.

Drug-Induced Parkinsonism Manifesting as Gait Freezing in a Patient With Traumatic Brain Injury: A Case Report

BACKGROUND

Among the neuropsychiatric complications commonly induced by traumatic brain injury (TBI), behavioral disorders, such as agitation and aggression, can hinder neurological recovery and deteriorate rehabilitation outcomes. Pharmacological treatment for behavioral disorders might be beneficial but could lead to drug-induced parkinsonism. We report a case of a patient with drug-induced parkinsonism manifested as freezing of gait after TBI, which improved with the cessation of the offending drugs and comprehensive rehabilitation.

CASE PRESENTATION

A 35-year-old male patient left with a TBI after a car accident was referred to our hospital. He had been on many neuropsychiatric medications, including atypical antipsychotics, for his agitated behaviors. He could walk independently but showed freezing of gait at the initiation of his gait, when turning to the side, when reaching his destination, and passing through narrow corridors. Under the impression of drug-induced parkinsonism, we gradually tapered the patient off his neuropsychiatric medications. He also underwent comprehensive rehabilitation, including gait training under visual and auditory cues and balance training. Five weeks after admission to the hospital, the patient's freezing of gait improved, with disappearance of his hesitation at gait initiation and a decreased freezing duration while turning around.

CONCLUSIONS

This is a rare report of drug-induced parkinsonism manifested as freezing of gait, which showed improvement after discontinuation of the causative drugs and subsequent rehabilitation.

Classics in Chemical Neuroscience: Donepezil

The discovery of acetylcholine and acetylcholinesterase provided the first insight into the intricacies of chemical signal transduction and neuronal communication. Further elucidation of the underlying mechanisms led to an attendant leveraging of this knowledge via the synthesis of new therapeutics designed to control aberrant biochemical processes. The central role of the cholinergic system within human memory and learning, as well as its implication in Alzheimer's disease, has made it a point of focus within the neuropharmacology and medicinal chemistry communities. This review is focused on donepezil and covers the background, synthetic routes, structure-activity relationships, binding interactions with acetylcholinesterase, pharmacokinetics and metabolism, efficacy, adverse effects, and historical importance of this leading therapeutic in the treatment of Alzheimer's disease and true Classic in Chemical Neuroscience.

Catecholaminergic based therapies for functional recovery after TBI

Among the many pathophysiologic consequences of traumatic brain injury are changes in catecholamines, including dopamine, epinephrine, and norepinephrine. In the context of TBI, dopamine is the one most extensively studied, though some research exploring epinephrine and norepinephrine have also been published. The purpose of this review is to summarize the evidence surrounding use of drugs that target the catecholaminergic system on pathophysiological and functional outcomes of TBI using published evidence from pre-clinical and clinical brain injury studies. Evidence of the effects of specific drugs that target catecholamines as agonists or antagonists will be discussed. Taken together, available evidence suggests that therapies targeting the catecholaminergic system may attenuate functional deficits after TBI. Notably, it is fairly common for TBI patients to be treated with catecholamine agonists for either physiological symptoms of TBI (e.g. altered cerebral perfusion pressures) or a co-occuring condition (e.g. shock), or cognitive symptoms (e.g. attentional and arousal deficits). Previous clinical trials are limited by methodological limitations, failure to replicate findings, challenges translating therapies to clinical practice, the complexity or lack of specificity of catecholamine receptors, as well as potentially counfounding effects of personal and genetic factors. Overall, there is a need for additional research evidence, along with a need for systematic dissemination of important study details and results as outlined in the common data elements published by the National Institute of Neurological Diseases and Stroke. Ultimately, a better understanding of catecholamines in the context of TBI may lead to therapeutic advancements. This article is part of a Special Issue entitled SI:Brain injury and recovery.

The Role of Dopamine and Its Dysfunction as a Consequence of Oxidative Stress

Dopamine is a neurotransmitter that is produced in the substantia nigra, ventral tegmental area, and hypothalamus of the brain. Dysfunction of the dopamine system has been implicated in different nervous system diseases. The level of dopamine transmission increases in response to any type of reward and by a large number of strongly additive drugs. The role of dopamine dysfunction as a consequence of oxidative stress is involved in health and disease. Introduce new potential targets for the development of therapeutic interventions based on antioxidant compounds. The present review focuses on the therapeutic potential of antioxidant compounds as a coadjuvant treatment to conventional neurological disorders is discussed.