The comparative study of clinical efficacy and safety of baclofen vs tolperisone in spasticity caused by spinal cord injury

Drug Repurposing for Spinal Cord Injury: Progress Towards Therapeutic Intervention for Primary Factors and Secondary Complications

Spinal cord injury (SCI) encompasses a plethora of complex mechanisms like the involvement of major cell death pathways, neurodegeneration of spinal cord neurons, overexpression of glutaminergic transmission and inflammation cascade, along with different co-morbidities like neuropathic pain, urinary and sexual dysfunction, respiratory and cardiac failures, making it one of the leading causes of morbidity and mortality globally. Corticosteroids such as methylprednisolone and dexamethasone, and non-steroidal anti-inflammatory drugs such as naproxen, aspirin and ibuprofen are the first-line treatment options for SCI, inhibiting primary and secondary progression by preventing inflammation and action of reactive oxygen species. However, they are constrained by a short effective drug administration window and their pharmacological action being limited to symptomatic relief of the secondary effects related to spinal cord injury only. Although post-injury rehabilitation treatments may enable functional recovery, they take a long time to show results. Drug repurposing might be an innovative method for expanding therapy alternatives, utilising drugs that are already approved by various esteemed federal agencies throughout the world. Reutilising a drug molecule to treat SCI can eliminate the need for expensive and lengthy drug discovery processes and pave the way for new therapeutic approaches in SCI. This review summarises marketed drugs that could be repurposed based on their safety and efficacy data. We also discuss their mechanisms of action and provide a list of repurposed drugs under clinical trials for SCI therapy.

Intrathecal and Oral Baclofen Use in Adults With Spinal Cord Injury: A Systematic Review of Efficacy in Spasticity Reduction, Functional Changes, Dosing, and Adverse Events

OBJECTIVE

To examine the efficacy, dosing, and safety profiles of intrathecal and oral baclofen in treating spasticity after spinal cord injury (SCI).

DATA SOURCES

PubMed and Cochrane Databases were searched from 1970-2018 with keywords baclofen, spinal cord injury, and efficacy.

STUDY SELECTION

The database search yielded 588 sources and 10 additional relevant publications. After removal of duplicates, 398 publications were screened.

DATA EXTRACTION

Data were extracted using the following population, intervention, comparator, outcomes, and study designs criteria: studies including adult patients with SCI with spasticity; the intervention could be oral or intrathecal administration of baclofen; selection was inclusive for control groups, surgical management, rehabilitation, and alternative pharmaceutical agents; outcomes were efficacy, dosing, and adverse events. Randomized controlled trials, observational studies, and case reports were included. Meta-analyses and systematic reviews were excluded.

DATA SYNTHESIS

A total of 98 studies were included with 1943 patients. Only 4 randomized, double-blinded, and placebo-controlled trials were reported. Thirty-nine studies examined changes in the Modified Ashworth Scale (MAS; 34 studies) and Penn Spasm scores (Penn Spasm Frequency; 19 studies), with average reductions of 1.7±1.3 and 1.6±1.4 in individuals with SCI, respectively. Of these data, a total of 6 of the 34 studies (MAS) and 2 of the 19 studies (Penn Spasm Frequency) analyzed oral baclofen. Forty-three studies addressed adverse events with muscle weakness and fatigue frequently reported.

CONCLUSIONS

Baclofen is the most commonly-prescribed antispasmodic after SCI. Surprisingly, there remains a significant lack of large, placebo-controlled, double-blinded clinical trials, with most efficacy data arising from small studies examining treatment across different etiologies. In the studies reviewed, baclofen effectively improved spasticity outcome measures, with increased efficacy through intrathecal administration. Few studies assessed how reduced neural excitability affected residual motor function and activities of daily living. A host of adverse events were reported that may negatively affect quality of life. Comparative randomized controlled trials of baclofen and alternative treatments are warranted because these have demonstrated promise in relieving spasticity with reduced adverse events and without negatively affecting residual motor function.

[Spasticity: from pathophysiology to treatment]

The article presents modern views on the pathophysiology of spasticity, which is a frequent disabling consequence to the upper motor neuron (UMN) damage. Morphological and functional system of motion organization and the changes after the UMN damage is considered. The authors analyze existing definitions of spasticity. Stages of spasticity development are described in the context of neuroplasticity as well as in the framework of pathogenesis and sanogenesis. Existing ideas of its pathogenesis are compared with the typical clinical symptoms. The occurring pathological processes in muscles, tendons and joints that can aggravate the development of spasticity and complicate the diagnosis are considered. In addition, the main pathological spasticity patterns are described and the current development of diagnostic techniques is estimated. A review of main methods of spasticity treatment is presented. Special attention is paid to the botulinum neurotoxin type A (BoNT) preparations and central action muscle relaxants. The pathophysiological basement for complex treatment of spasticity as a part of the general rehabilitation process is given, so that the BoNT can be considered as the obligatory element of standard rehabilitation programs.

Efficacy and Safety of Botulinum Toxin Type A in Spasticity Caused by Spinal Cord Injury: A Randomized, Controlled Trial

Background

Baclofen is approved by the US FDA to treat spasticity, but its sustained use may cause drug addiction. The objective of this study was to compare the efficacy and safety of botulinum toxin type A versus baclofen in spasticity.

Material/Methods

A total of 336 patients who had spasticity caused by spinal cord injury were enrolled in a randomized (in 1: 1: 1: ratio) for placebo, controlled trial. Patients had received baclofen (BA group, n=112), local intramuscular injection of 500 U Botulinum toxin type A (BTI group, n=112), or physical therapies alone (placebo group, n=112). Modified Ashworth scale (mAS) score, disability assessment scale (DAS) score, modified medical research council (mMRC) score, the Barthel Index (BI) score, and treatment-emergent adverse effects were evaluated during the follow-up period. Wilcoxon test or one-way ANOVA/Tukey post hoc tests were performed at 95% of confidence level.

Results

Baclofen (1.504±0.045 vs. 1.53±0.06, p=0.003, q=4.068) and botulinum toxin type A (1.49±0.09 vs. 1.528±0.15, p=0.0224, q=3.5541) had improved mAS scores after 2 weeks. Baclofen had a more strongly improved DAS score than botulinum toxin type A at 4 (p=0.0496, q=3.48) and 6 (p<0.0001, q=6.48) weeks. Baclofen and botulinum toxin type A had consistently improved BI scores. Baclofen caused asthenia and sleepiness, while botulinum toxin type A caused bronchitis and elevated blood pressure.

Conclusions

Botulinum toxin type A may be an effective therapeutic option for spasticity caused by spinal cord injury.