Pharmacotherapy for traumatic brain injury: focus on sympathomimetics

Efficacy and Harms of Pharmacological Interventions for Neurobehavioral Symptoms in Post-Traumatic Amnesia after Traumatic Brain Injury: A Systematic Review

Many individuals in post-traumatic amnesia (PTA) following traumatic brain injury (TBI) experience neurobehavioral symptoms (NBS) in addition to disorientation and amnesia. These symptoms are associated with low rehabilitation engagement, self-inflicted harm, and risk of violence. The aim of this systematic review was to evaluate the efficacy and harms of pharmacological interventions for NBS in PTA following TBI in adults. Studies in English published before December 2017 were reviewed. Six databases were searched, with additional hand searching of key journals, clinical trials registries, and international drug regulators. Evidence quality was assessed using Joanna Briggs Institute Critical Appraisal Instruments. Thirteen studies were identified: three randomized controlled trials (RCTs), three cohort studies, and seven case series. In the RCTs, neither amantadine nor sertraline reduced NBS. Less rigorous studies reported reduced NBS in patients administered haloperidol, ziprasidone, carbamazepine, amitriptyline, desipramine, and varied neuroleptics. There is a paucity of well-designed, adequately powered and controlled studies of pharmacological interventions for NBS in PTA. More research is needed to provide evidence-based treatment recommendations and improve care.

Pharmacological Stimulation of Neuronal Plasticity in Acquired Brain Injury

INTRODUCTION

Brain injuries are one of the leading causes of disability worldwide. It is estimated that nearly half of patients who develop severe sequelae will continue with a chronic severe disability despite having received an appropriate rehabilitation program. For more than 3 decades, there has been a worldwide effort to investigate the possibility of pharmacologically stimulating the neuroplasticity process for enhancing the recovery of these patients.

OBJECTIVE

The objective of this article is to make a critical and updated review of the available evidence that supports the positive effect of different drugs on the recovery from brain injury.

METHOD

To date, there have been several clinical trials that tested different drugs that act on different neurotransmitter systems: catecholaminergic, cholinergic, serotonergic, and glutamatergic. There is both basic and clinical evidence that may support some positive effect of these drugs on motor, cognitive, and language skills; however, only few of the available studies are of sufficient methodological quality (placebo controlled, randomized, blinded, multicenter, etc) to make solid conclusions about their beneficial effects.

CONCLUSIONS

Currently, the pharmacological stimulation of neuroplasticity still does not have enough scientific evidence to make a systematic therapeutic recommendation for all patients, but it certainly is a feasible and very promising field for future research.

Efficacy and harms of pharmacological interventions for neurobehavioral symptoms in post traumatic amnesia after traumatic brain injury: a systematic review and meta-analysis protocol

REVIEW OBJECTIVE/QUESTION

The objective of this systematic review is to synthesize the best available evidence on the effectiveness and harms of pharmacotherapy as compared to all types of comparators for the management of neurobehavioral symptoms in post-traumatic amnesia in adults aged 16 years and over who have sustained a traumatic brain injury. This review forms part of a larger project which aims to gather the evidence for the pharmacological treatment of neurobehavioral symptoms post traumatic brain injury as a prelude to the development of a clinical guideline.

A Threshold Shear Force for Calcium Influx in an Astrocyte Model of Traumatic Brain Injury

Traumatic brain injury (TBI) refers to brain damage resulting from external mechanical force, such as a blast or crash. Our current understanding of TBI is derived mainly from in vivo studies that show measurable biological effects on neurons sampled after TBI. Little is known about the early responses of brain cells during stimuli and which features of the stimulus are most critical to cell injury. We generated defined shear stress in a microfluidic chamber using a fast pressure servo and examined the intracellular Ca(2+) levels in cultured adult astrocytes. Shear stress increased intracellular Ca(2+) depending on the magnitude, duration, and rise time of the stimulus. Square pulses with a fast rise time (∼2 ms) caused transient increases in intracellular Ca(2+), but when the rise time was extended to 20 ms, the response was much less. The threshold for a response is a matrix of multiple parameters. Cells can integrate the effect of shear force from repeated challenges: A pulse train of 10 narrow pulses (11.5 dyn/cm(2) and 10 ms wide) resulted in a 4-fold increase in Ca(2+) relative to a single pulse of the same amplitude 100 ms wide. The Ca(2+) increase was eliminated in Ca(2+)-free media, but was observed after depleting the intracellular Ca(2+) stores with thapsigargin suggesting the need for a Ca(2+) influx. The Ca(2+) influx was inhibited by extracellular Gd(3+), a nonspecific inhibitor of mechanosensitive ion channels, but it was not affected by the more specific inhibitor, GsMTx4. The voltage-gated channel blockers, nifedipine, diltiazem, and verapamil, were also ineffective. The data show that the mechanically induced Ca(2+) influx commonly associated with neuron models for TBI is also present in astrocytes, and there is a viscoelastic/plastic coupling of shear stress to the Ca(2+) influx. The site of Ca(2+) influx has yet to be determined.

Melanocortins as potential therapeutic agents in severe hypoxic conditions

Melanocortin peptides with the adrenocorticotropin/melanocyte-stimulating hormone (ACTH/MSH) sequences and synthetic analogs have protective and life-saving effects in experimental conditions of circulatory shock, myocardial ischemia, ischemic stroke, traumatic brain injury, respiratory arrest, renal ischemia, intestinal ischemia and testicular ischemia, as well as in experimental heart transplantation. Moreover, melanocortins improve functional recovery and stimulate neurogenesis in experimental models of cerebral ischemia. These beneficial effects of ACTH/MSH-like peptides are mostly mediated by brain melanocortin MC(3)/MC(4) receptors, whose activation triggers protective pathways that counteract the main ischemia/reperfusion-related mechanisms of damage. Induction of signaling pathways and other molecular regulators of neural stem/progenitor cell proliferation, differentiation and integration seems to be the key mechanism of neurogenesis stimulation. Synthesis of stable and highly selective agonists at MC(3) and MC(4) receptors could provide the potential for development of a new class of drugs for a novel approach to management of severe ischemic diseases.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest regarding a broad scope of topics are abstracted monthly.