Effectiveness of gabapentin in controlling spasticity: a quantitative study

Feasibility of gabapentin as an intervention for neurorecovery after an acute spinal cord injury: Protocol

Introduction

This protocol is describing the first ever prospective, mock-efficacy, dose exploration trial design testing the feasibility of administering gabapentin in the acute setting as an intervention for neurorecovery. Gabapentin is an FDA-approved medication for treating seizures and postherpetic neuralgia and is used broadly off-label for neuropathic pain management for many conditions, including spinal cord injury. Emerging data suggests that when given early after spinal cord injury onset and in low-medium doses, gabapentin may have properties that promote recovery of neurological function. The objective of this trial is to assess the feasibility of conducting an efficacy trial in which gabapentin is started early after injury, is restricted in its dose, and is not used for pain management.

Methods and analysis

Forty-two people aged 18 years or older with any level and any severity of spinal cord injury induced by a trauma will be enrolled, randomized, and have the first dose of study medication by 120 h post-injury onset. Participants will be randomly assigned to one of three groups: 600, 1,800 mg/day gabapentin, or placebo. Study medication will be given for a 90-day duration. Blinded assessments will be obtained at 7 days post-injury (baseline), 30 days post-injury (interim), after the 90-day treatment duration/approximately 3 months post-injury (end of treatment), and at 6 months post-injury (end of study). The key analysis parameters will evaluate feasibility of recruitment of target population, delivery of drug treatment protocol, maintenance of blinding, and retention of participants.

Discussion

Outputs from this trial will inform research and clinical practice on the effects of manipulating gabapentin for non-pain management purposes in the acute setting and will guide the development of a properly powered efficacy trial of gabapentin as an intervention for neurorecovery in spinal cord injury.

Ethics and dissemination

The study was approved by the MetroHealth Institutional Review Board (IRB21-00609) and registered at clinicaltrials.gov prior to enrolling any participants. Dissemination will include peer-reviewed publications, presentations at professional conferences and in the community, and through other healthcare and public venues.

Clinical trial registration

www.ClinicalTrials.gov, identifier: NCT05302999; protocol version 1.1 approved 05/23/2022.

Trial funding

National Institute on Disability, Independent Living and Rehabilitation Research.

Therapeutics in the Management of Spasticity

Spasticity is commonly defined as a velocity-dependent increase in tonic stretch re flexes that results from a variety of disorders affecting the brain and spinal cord. Treat ment of spasticity is generally considered when the increase in tone interferes with functional activities, such as positioning, mobility, or daily cares, when it is painful, or when it leads to complications such as contractures or skin breakdown. This re view discusses the pathophysiology of spasticity and details the various treatments avail able, including physical and occupational therapy modalities, use of splints and or thoses, oral and intrathecal medications, nerve blocks, botulinum toxin injections, and orthopedic and neurosurgical interventions.

A Brain Motor Control Assessment (BMCA) protocol for upper limb function

The Brain Motor Control Assessment (BMCA) protocol is a surface electromyography (sEMG)-based measure of motor output from central nervous system during a variety of reflex and voluntary motor tasks performed under strictly controlled conditions. The aim of this study was to evaluate the BMCA protocol for upper limb with the addition of shoulder voluntary tasks. The voluntary response index (VRI) was calculated from quantitative analysis of sEMG data during defined voluntary movement in neurologically intact people for comparison with that of patients after neurological injuries. The BMCA protocol included one bilateral and 4 unilateral voluntary tasks at different joints of both arms. The VRI, measured from 19 neurologically intact participants, comprises the total muscle activity recorded for the voluntary motor task (magnitude). The calculated similarity index (SI) for each phase of each task show the similarity of “the distribution of activity across the recorded muscles” for that task in this group off participants. Results: The VRI magnitude values from right and left sides for different tasks showed no significant difference (ANOVA: F_Side: 0.09, P = 0.77). Therefore these values were pooled before calculating SI. SI values were higher for tasks against gravity: elbow flexion (0.99±0.03), wrist flexion with palm up (0.98±0.03) and wrist extension with palm down (0.97±0.07). On the other hand, the SI values were the lowest for bilateral shoulder abduction (0.84±0.08) and shoulder adduction (0.84±0.08). Conclusion: To validate this index for clinical use, serial studies on patients with neurological impairments should be performed. Tasks involving movement against gravity may be more suitable in future BMCAs.

The efficacy of gabapentin versus stabilization splint in management of sleep bruxism

PURPOSE

This study aimed to determine if the use of gabapentin is more efficacious than a stabilization splint with regard to the intensity of masseter muscle contractions and/or sleep quality for patients experiencing sleep bruxism (SB).

MATERIALS AND METHODS

Twenty patients with SB participated in this clinical study. They were randomly divided into two treatment groups: stabilization splint group (n = 10) and gabapentin group (n = 10). The first polysomnographic examination was performed before the beginning of the experiment for all the participants. At the end of a 2-month period of stabilization splint therapy or gabapentin usage, a second polysomnographic recording was made.

RESULTS

Statistically significant reductions in the number of SB episodes per hour and per night, bruxism time index, total duration of SB episodes per night and number of SB episodes in stages NR I and NR II (p < 0.05) were observed in both groups after treatment. Both treatments significantly reduced the mean intensity of masseter muscle contractions during SB episodes. Moreover, the participants treated with gabapentin showed a significant improvement in total sleep time, slow wave sleep (stage III), and sleep efficiency (p < 0.05).

CONCLUSIONS

Gabapentin could be an effective treatment modality in SBs, especially in those with poor sleep quality.

Effects of gabapentin on muscle spasticity and both induced as well as spontaneous autonomic dysreflexia after complete spinal cord injury

We recently reported that the neuropathic pain medication, gabapentin (GBP; Neurontin), significantly attenuated both noxious colorectal distension (CRD)-induced autonomic dysreflexia (AD) and tail pinch-induced spasticity compared to saline-treated cohorts 2–3 weeks after complete high thoracic (T4) spinal cord injury (SCI). Here we employed long-term blood pressure telemetry to test, firstly, the efficacy of daily versus acute GBP treatment in modulating AD and tail spasticity in response to noxious stimuli at 2 and 3 weeks post-injury. Secondly, we determined whether daily GBP alters baseline cardiovascular parameters, as well as spontaneous AD events detected using a novel algorithm based on blood pressure telemetry data. At both 14 and 21 days after SCI, irrespective of daily treatment, acute GBP given 1 h prior to stimulus significantly attenuated CRD-induced AD and pinch-evoked tail spasticity; conversely, acute saline had no such effects. Moreover, daily GBP did not alter 24 h mean arterial pressure (MAP) or heart rate (HR) values compared to saline treatment, nor did it reduce the incidence of spontaneous AD events compared to saline over the three week assessment period. Power spectral density (PSD) analysis of the MAP signals demonstrated relative power losses in mid frequency ranges (0.2–0.8 Hz) for all injured animals relative to low frequency MAP power (0.02–0.08 Hz). However, there was no significant difference between groups over time post-injury; hence, GBP had no effect on the persistent loss of MAP fluctuations in the mid frequency range after injury. In summary, the mechanism(s) by which acute GBP treatment mitigate aberrant somatosensory and cardiophysiological responses to noxious stimuli after SCI remain unclear. Nevertheless, with further refinements in defining the dynamics associated with AD events, such as eliminating requisite concomitant bradycardia, the objective repeatability of automatic detection of hypertensive crises provides a potentially useful tool for assessing autonomic function pre- and post-SCI, in conjunction with experimental pharmacotherapeutics for neuropathic pain, such as GBP.

Latest approaches for the treatment of spasticity and autonomic dysreflexia in chronic spinal cord injury

Two of the most prevalent secondary complications following spinal cord injury (SCI), besides loss of function and/or sensation below the level of injury, are uncontrolled muscle spasticity and hypertensive autonomic dysreflexia. Despite the desires of the SCI community, there have been few advances in the treatment and/or management of these fundamental impediments to the quality of life associated with chronic SCI. Therefore, the purpose of this review is to focus on current drug treatment strategies that alleviate symptoms of spasticity and autonomic dysfunction. Subsequently, looking ahead, we discuss whether individuals suffering from autonomic dysreflexia and/or muscle spasms can take certain compounds that specifically and rapidly block the neurotransmission of pain into the injured spinal cord to get rapid relief for both aberrant reflexes for which painful stimuli below the level of SCI are common precipitants.

Gabapentin for spasticity and autonomic dysreflexia after severe spinal cord injury

STUDY DESIGN

Using a complete transection spinal cord injury (SCI) model at the fourth thoracic vertebral level in adult rats, we evaluated whether blocking noxious stimuli below the injury diminishes abnormal somatic and autonomic motor reflexes, manifested in muscular spasticity and hypertensive autonomic dysreflexia, respectively. Gabapentin (GBP) is well tolerated and currently used to manage neuropathic pain in the SCI population; evidence suggests that it acts to decrease presynaptic glutamate release. As clinical evidence indicates that GBP may suppress muscular spasticity in the chronic SCI population, we hypothesized that preventing neurotransmission of noxious stimuli with GBP eliminates a critical physiological link to these distinct, debilitating SCI-induced secondary impairments.

OBJECTIVES

Behavioural assessments of tail muscle spasticity and mean arterial blood pressure responses to noxious somatic and/or visceral stimulation were used to test the effects of GBP on these abnormal reflexes.

SETTING

Lexington, Kentucky.

METHODS

We used femoral artery catheterization and radio-telemetric approaches to monitor blood pressure alterations in response to noxious colorectal distension (CRD) weeks after complete SCI.

RESULTS

At 2-3 weeks post-SCI, acute GBP administration (50 mg kg(-1), i.p.) significantly attenuated both autonomic dysreflexia and tail spasticity induced by noxious stimuli compared with saline-treated cohorts.

CONCLUSION

These results show, for the first time, that a single-pharmacological intervention, GBP, can effectively attenuate the manifestation of both muscular spasticity and autonomic dysreflexia in response to noxious stimuli.

Development and validation of Patient Reported Impact of Spasticity Measure (PRISM)

Persons with spinal cord injury (SCI) may experience a range of symptoms typically labeled "spasticity." Previous efforts to develop assessment tools that measure spasticity have failed to represent the experiences of persons who live with the condition. The purpose of this multicenter study was to develop an instrument that measures the impact of spasticity on quality of life. Based on 24 semistructured interviews, a developmental form of the Patient Reported Impact of Spasticity Measure (PRISM) was constructed. The developmental PRISM was administered to 180 persons at five sites. Subscales were developed based on factor analytic results. Evidence for the reliability and validity of the scores was evaluated. Seven subscales were developed, including one that measures the positive effects of spasticity. Results of reliability and validity assessments indicate that the PRISM subscale scores effectively measure the impact of spasticity in the population of veterans with SCI.

Pregabalin in the treatment of spasticity: a retrospective case series

PURPOSE

To evaluate the therapeutic effects of the GABA analogue, pregabalin, on patients with conditions producing spasticity who had not responded to, or experienced problems with side-effects of the available anti-spasticity agents.

METHOD

A retrospective case series review of 22 patients who were prescribed open label Pregabalin as monotherapy for spasticity, starting with 75 mg bd and increasing to 300 mg bd. Twenty one of these patients had previously tried gabapentin, 19 had tried baclofen, 7 had tried tizanidine and 3 had tried dantrolene.

RESULTS

Twelve patients perceived a definite reduction in symptoms of spasticity with pregabalin, and 9 continued to take it. Eight patients experienced significant side-effects which limited its use, 5 experienced no beneficial or adverse effects.

CONCLUSIONS

Pregabalin may be of value as a systemic agent in the treatment of spasticity, although properly controlled studies with clearly defined outcome measures are required to confirm this finding. This is relevant to the study of disability and rehabilitation because of the difficulties encountered in the management of spasticity and the impact that this can have on the rehabilitation of individuals with neurological conditions.

Efficacy of pregabalin and gabapentin for neuropathic pain in spinal-cord injury: an evidence-based evaluation of the literature

BACKGROUND

Spinal-cord injury (SCI) is a leading cause of neuropathic pain (NP). Current pharmaceutical treatments for NP in SCI patients are not effective. Two promising options are gabapentin (GP) and pregabalin (PB). Their predominant mechanism of action is believed to be the inhibition of calcium currents, leading in turn to reduced neurotransmitter release and attenuation of postsynaptic excitability. This could explain much of their efficacy in the treatment of both seizure disorders and pain syndromes. However, evidence for their efficacy in attenuating NP of SCI is still controversial.

OBJECTIVE

To efficiently integrate valid information and provide a basis for rational decision making, through determining PB and GP efficacy in treating NP in SCI.

METHODS

Literature was systematically reviewed. Medline, Embase, CINAHL and Cochrane Database were searched using search terms 'gabapentin', 'pregabalin', 'neurontin', 'lyrica', 'neuropathic pain' and 'spinal-cord injury'. Studies were assessed independently by two authors.

RESULTS

Five studies were eligible for inclusion. Two of them studied PB and three GP. Both GP and PB appear to be efficacious for NP in SCI. A clear comparison between the two drugs could not be performed. The literature data suggest that PB is more efficacious than GP in many important variables for NP in SCI, although PB use is followed by more side effects than GP. PB reduced Visual Analogue Score (VAS) in both studies (P < 0.001 and P = 0.016). On the other hand, for GP a maximum dosage of 3,600 mg/day reduced VAS score (P = 0.000), whereas a maximum dosage of 1,200 mg/day failed to do so.

CONCLUSION

There is a lack of studies comparing GP and PB in treating NP in SCI. This systematic review indicates the possible efficacy of PB and GP in NP of SCI. Recommendations for future research to inform clinical practice should include cost-effectiveness studies and dose-response analysis in order to determine the schema employed and the duration of treatment.

The excitatory:inhibitory ratio model (EIR model): An integrative explanation of acute autonomic overactivity syndromes

Numerous medical conditions present with acute and severe autonomic and muscular overactivity. These syndromes include Neuroleptic Malignant Syndrome, Serotonin Syndrome, Dysautonomia (or paroxysmal sympathetic storms) following acquired brain injury, Autonomic Dysreflexia, Parkinsonian-Hyperpyrexia Syndrome, Malignant Catatonia, intrathecal baclofen withdrawal, Malignant Hyperthermia, Stiff Man Syndrome and Irukandji Syndrome. In their worst forms, each of these syndromes are relatively rare, are treated by different medical specialties and show widely varying pathophysiology. Most are considered to be medical emergencies and share significant mortality rates. Previous authors have noted similarities between some of these conditions, prompting the suggestion that a single common mechanism may underlie their clinical presentation. However, the development of such an integrative model has not occurred. This paper presents a short review of the clinical syndromes, grouped by the location of pathology and mechanism of action. From this background, an integrative framework termed the excitatory:inhibitory ratio (EIR) model is presented. The EIR model consists of two inter-related networks operating at spinal and brainstem levels. The model is evaluated against pre-clinical scientific research, known pathways, each disorder's pathophysiology (where this is known) and variable severity, and used to explain the reasons behind the efficacy of current treatment regimes. Circumstantial evidence for an expanded aetiology for Malignant Hyperthermia is provided and generic treatment strategies for a number of other conditions are suggested. Finally, minor modifications to this model provide a basis to begin to explain less severe, regional "overlap" syndromes.

Gabapentin for decerebrate rigidity: a case report

A 48-year-old woman suddenly lost consciousness as a result of a right rostral pontine tegmentum haemorrhage. The patient presented with decerebrate rigidity (DR) and regained full consciousness 5 days after the initial onset. The patient was given gabapentin 1200 mg/day nasogastrically and her DR significantly improved, although other antiepileptic drugs such as phenytoin and carbamazepine were given in larger dosages to decrease muscle hypertonicity. The patients' preserved consciousness and motor-evoked potentials to transcranial magnetic stimulation indicated a derangement of the extrapyramidal tracts with preservation of the pyramidal tracts. This case report discusses the possible mechanisms of action of gabapentin in DR.

Double-blind crossover trial of gabapentin in SPG4-linked hereditary spastic paraplegia

Patients with hereditary spastic paraplegia (HSP) are often treated with antispastic drugs to relieve symptoms but documentation is lacking. In this study, gabapentin was tested in a double-blind crossover trial on a group of patients with HSP and linkage to the SPG4 locus. There was no difference between periods with gabapentin and placebo treatment in clinical assessment, self-reported parameters or paired transcranial magnetic stimulation evaluation of motor cortical excitability.

Efectividad de la gabapentina en el tratamiento de la espasticidad: estudio aleatorizado, a doble ciego y controlado con placebo

BACKGROUND AND OBJECTIVE

We aimed to demonstrate the efficacy and safety of gabapentin for the treatment of spasticity in patients with upper motor neuron syndrome.

PATIENTS AND METHOD

Thirty patients with pyramidal-tract lesions were randomized to up to 3,600 mg/day of gabapentin (n = 15) or placebo (n = 15) in a double-blind, pilot 10-week trial. The primary efficacy variable was the Ashworth Scale score. Secondary variables included the Spasm Frequency Scale, maximal range of movement, H/M Amplitude Ratio, and the Barthel Index for quality of life. Adverse events were recorded. All data were analyzed on an intent-to-treat basis.

RESULTS

Demographic and baseline characteristics were similar between the 2 treatment groups. The gabapentin group showed significant improvement in Ashworth Scale total scores, and scores for individual affected muscle groups. Fifteen of the randomized patients had spasms; the total Spasm Frequency Scale score was not significantly different between groups. Nevertheless, when affected individual muscle groups were analyzed, a significant effect of gabapentin vs placebo was observed at all visits. Gabapentin did not modify the scores of the range of movement, the H/M Amplitude Ratio, or the Barthel Index tests. No gait or displacement impairment were seen during treatment with gabapentin. Related adverse events occurred less frequently in the gabapentin group, and fewer gabapentin patients withdrew because of adverse events.

CONCLUSIONS

Gabapentin demonstrated efficacy and safety at doses between 2,700 and 3,600 mg/day as a therapy for the spasticity associated with the upper motor neuron syndrome.

Toward an objective interpretation of surface EMG patterns: a voluntary response index (VRI)

Individuals with incomplete spinal cord injuries (SCI) retain varying degrees of voluntary motor control. The complexity of the motor control system and the nature of the recording biophysics have inhibited efforts to develop objective measures of voluntary motor control. This paper proposes the definition and use of a voluntary response index (VRI) calculated from quantitative analysis of surface electromyographic (sEMG) data recorded during defined voluntary movement as a sensitive measure of voluntary motor control in such individuals. The VRI is comprised of two numeric values, one derived from the total muscle activity recorded for the voluntary motor task (magnitude), and the other from the sEMG distribution across the recorded muscles (similarity index (SI)). Calculated as a vector, the distribution of sEMG from the test subject is compared to the average vector calculated from sEMG recordings of the same motor task from 10 neurologically intact subjects in a protocol called brain motor control assessment (BMCA). To evaluate the stability of the VRI, a group of five healthy subjects were individually compared to the prototype, average healthy-subject vectors for all of the maneuvers. To evaluate the sensitivity of this method, the VRI was obtained from two SCI subjects participating in other research studies. One was undergoing supported treadmill ambulation training, and the other a controlled withdrawal of anti-spasticity medications. The supported treadmill training patient's VRI, calculated from pre- and post-training BMCA recordings, reflected the qualitative changes in sEMG patterns and functional improvement of motor control. The VRI of the patient followed by serial BMCA during medication withdrawal also reflected changes in the motor control as a result of changes in anti-spasticity medication. To validate this index for clinical use, serial studies using larger numbers of subjects with compromised motor control should be performed.

GABAB Receptors Do Not Mediate the Inhibitory Actions of Gabapentin on the Spinal Reflex in Rats

The clinical effectiveness of gabapentin for the treatment of epilepsy, spasticity, and neuropathic pain has been established. The mechanisms responsible for those actions, however, are still not clearly understood. We have recently demonstrated that gabapentin reduces the spinal reflex in rats via mechanisms that do not involve gamma-aminobutyric acid (GABA)A receptors. In the study, we attempted to explore the involvement of GABAB receptors in gabapentin-induced inhibition of the spinal reflexes in spinalized rats. Stimulation of the dorsal root at L5 elicited the segmental mono-(MSR) and polysynaptic reflex (PSR) in the ipsilateral ventral root. The microinjection of gabapentin (1.5 and 5 nmol) into the ventral horn reduced both MSR and PSR, whereas the injection into the dorsal horn only inhibited the PSR, indicating that systemic gabapentin inhibits the MSR at the ventral horn and it inhibits the PSR at both the ventral and dorsal horns. The GABAB-receptor antagonist CGP35348 (0.5 nmol) injected into the ventral horn antagonized the inhibition of the spinal reflexes by the GABAB-receptor agonist baclofen (i.v.) but not by gabapentin (i.v.). Thus, GABAB receptors do not appear to contribute to the gabapentin-induced inhibition of the spinal reflex.

Orally Delivered Baclofen to Control Spastic Hypertonia in Acquired Brain Injury

To determine if oral/systemic delivery of baclofen can effectively decrease spastic hypertonia due to acquired brain injury (traumatic brain injury, stroke, anoxia, or encephalopathy). Tertiary care outpatient rehabilitation center directly attached to a university hospital. Patients were a convenience sample recruited consecutively who had been referred for treatment of their spastic hypertonia to our spasticity clinic over a 5-year period. The spastic hypertonia was due to an acquired brain injury by either traumatic brain injury (TBI), stroke, or anoxic brain injury. All patients were more than 6 months postinjury or illness. Retrospective review of patients before and after initiation of treatment with oral baclofen, per standardized clinical data sheets. Thirty-five patients (22 TBI patients) were started on oral baclofen and were reevaluated between 1 to 3 months after initiation of treatment. Data for motor tone (Ashworth scores), spasm scores (Penn spasm frequency score), and deep tendon reflex scores were collected on the affected upper extremity (UE) and lower extremity (LE) side(s). Normal extremities were not assessed. Differences over time were assessed via descriptive statistics and Wilcoxon signed-rank. After 1 to 3 months of treatment when subjects had reached their maximal tolerated dosage, the average LE Ashworth score in the affected lower extremities (LEs) decreased from 3.5 to 3.2 (P =.0003), the reflex score decreased from 2.5 to 2.2 (P =.0274), and there was no statistical difference in the spasm score (P >.05). When the 22 TBI patients are analyzed separately, the average LE Ashworth score decreased from 3.5 to 3.2 (P =.0044) and the reflex score decreased from 2.7 to 2.0 (P =.0003). There was no statistically significant change in UE tone, spasm frequency, or reflexes after 1 to 3 months of treatment (P >.05). The average dosage at follow-up was 57 mg/day of baclofen (range 15-120 mg/day). There was a 17% incidence of somnolence that limited the maximum daily dosage of the medication. The oral delivery of baclofen is capable of reducing LE spastic hypertonia resulting from acquired brain injury. The lack of effect upon the upper extremities may be due to receptor specificity issues. GABA-B receptors may be less involved in the modulation of UE spastic hypertonia.

Gabapentin: pharmacology and its use in pain management

Although its exact mode of action is not known, gabapentin appears to have a unique effect on voltage-dependent calcium ion channels at the postsynaptic dorsal horns and may, therefore, interrupt the series of events that possibly leads to the experience of a neuropathic pain sensation. Gabapentin is especially effective at relieving allodynia and hyperalgesia in animal models. It has been shown to be efficacious in numerous small clinical studies and case reports in a wide variety of pain syndromes. Gabapentin has been clearly demonstrated to be effective for the treatment of neuropathic pain in diabetic neuropathy and postherpetic neuralgia. This evidence, combined with its favourable side-effect profile in various patient groups (including the elderly) and lack of drug interactions, makes it an attractive agent. Therefore, gabapentin should be considered an important drug in the management of neuropathic pain syndromes.

Pain and spasticity after spinal cord injury: mechanisms and treatment

STUDY DESIGN

A comprehensive survey of literature on the proposed mechanisms and treatment of pain and spasticity after spinal cord injury (SCI) was completed.

OBJECTIVES

To define the current understanding of these entities and to review various treatment options.

SUMMARY OF BACKGROUND DATA

The neurophysiologic basis of spasticity after SCI is well established. The mechanism of neuropathic pain after SCI remains conjectural, although considerable new data, much of it from animal models, now add to our understanding of this condition.

METHODS

A comprehensive search and review of the published literature was undertaken.

RESULTS

Treatment options for spasticity are effective and include oral medication (baclofen, tizanidine), intrathecal baclofen, and rarely, surgical rhizotomy or myelotomy. Selected patients with post-SCI pain can respond to surgical myelotomy (DREZ lesions) or intrathecal agents (e.g., morphine + clonidine), but the majority continue to suffer.

CONCLUSIONS

Medical and surgical treatments for spasticity are established and highly successful. Management of post-SCI pain remains a clinical challenge, as there is no uniformly successful medical or surgical treatment.

Pharmacotherapy of spasticity: oral medications and intrathecal baclofen

Spasticity is a common problem in children with neurologic impairment, particularly in those with cerebral palsy. Clinicians commonly make use of oral medications to attempt to reduce spasticity and increase function. Little has been published in the literature concerning the use of these medications in children and their effects on both muscle tone and function. This article is a review of the sites of action, side effects, and efficacy of benzodiazepines, baclofen, dantrolene sodium, alpha2-adrenergic agonists, and gabapentin. A brief review of intrathecal baclofen is included as well.

Gabapentin for chronic pain in spinal cord injury: a case report

A 30-year-old white woman with an L1 complete spinal cord injury (SCI) secondary to a gunshot wound in 1985, presented to a chronic pain service for evaluation. She had a 13-year history of chronic lower extremity pain. She described her discomfort as "throbbing, aching, and stabbing." She had tried many different medications, including opioids, Tegretol, and tricyclic antidepressants, without success. During the evaluation process, she admitted to being "angry, frustrated, and anxious." She was diagnosed with central pain after SCI. She was placed on gabapentin 300 mg 3 times daily; within 1 week, her visual analog pain scale fell from 95 mm to 27 mm, and her McGill Short Form pain score fell from 13 to 3. Her mood also vastly improved. This case report suggests that gabapentin should be studied as a therapeutic option for treating central pain post-SCI and should be considered as a viable, well-tolerated, low-toxicity tool.

Gabapentin for essential tremor: a multiple-dose, double-blind, placebo-controlled trial

Essential tremor (ET) is a common movement disorder that often becomes refractory to conventional pharmacologic management. Open-label studies suggest that gabapentin is efficacious for ET, but the results of controlled trials have been mixed. To determine the efficacy and tolerability of gabapentin in ET, we conducted a double-blind, placebo-controlled, cross-over trial evaluating two doses (1800 mg per day and 3600 mg per day; N = 25). Patients on other ET medications were maintained on their concurrent medications for 3 months prior to study initiation and throughout the study. Twenty patients (mean age, 69.9 +/- 6.1 yrs) completed the study. Overall, patient global assessments (p <0.05), observed tremor scores (p <0.005), water pouring scores (p <0.05), and activities of daily living scores (p <0.005) significantly improved. Accelerometry scores, spirographs, and investigator global impression scores did not improve. The results were similar for high and low doses. Statistical regression models did not demonstrate any significant predictors for response. Gabapentin may be effective in some cases of ET.

Gabapentin "add-on therapy" for idiopathic chronic hiccup (ICH)

The efficacy of cisapride, omeprazole, and baclofen (COB) for treatment of idiopathic chronic hiccup (ICH). was proven in several studies. The combination is considered, at present, to be "therapy of choice" for this condition. Substituting gabapentin for baclofen in baclofen resistant ICH cases can occasionally be successful. We present here cases where gabapentin was used successfully in combination with cisapride and omeprazole (COG/one patient) or as an "add-on" with cisapride, omeprazole, and baclofen (COBG/three patients). We conclude that, with baclofen and gabapentin, we are in possession of two substances that are, as a part of a combination therapy, quite effective for ICH. Because of the far more extensive experience with baclofen, we use it as a first-line therapy, together with omeprazole and cisapride. In cases where the results are not entirely satisfactory, the addition of gabapentin should be considered.

Drugs used to treat spasticity

Spasticity is a common and disabling symptom for many patients with upper motor neuron dysfunction. It results from interruption of inhibitory descending spinal motor pathways, and although the pathophysiology of spasticity is poorly understood, the final common pathway is overactivity of the alpha motor neuron. Therapy for spasticity is symptomatic with the aim of increasing functional capacity and relieving discomfort. Any approach to treatment should be multidisciplinary, including physical therapy, and possibly surgery, as well as pharmacotherapy. It is important that treatment be tailored to the individual patient, and that both patient and care giver have realistic expectations. Pharmacotherapy is generally initiated at low dosages and then gradually increased in an attempt to avoid adverse effects. Optimal therapy is the lowest effective dosage. Baclofen, diazepam, tizanidine and dantrolene are currently approved for use in patients with spasticity. In addition, clonidine (usually as combination therapy), gabapentin and botulinum toxin have shown efficacy, however, more studies are required to confirm their place in therapy. Intrathecal baclofen, via a surgically implanted pump and reservoir, may provide relief in patients with refractory severe spasticity.

Spasticity in spinal cord injury: self- and clinically rated intrinsic fluctuations and intervention-induced changes

OBJECTIVES

(1) To determine patterns of intrinsic fluctuations in spasticity, using repeated self-ratings, in subjects with spinal cord injury (SCI); and (2) To determine the relation between self-ratings of spasticity using a visual analogue scale (VAS) and clinical ratings of spasticity using the Modified Ashworth Scale (MAS) before and after spasticity-reducing treatment.

DESIGN

Part I: observational, prospective cross-sectional study; part II: experimental, prospective longitudinal study.

SETTING

Outpatient clinic of the Karolinska Hospital, Stockholm, Sweden.

PATIENTS

Forty-five persons with SCI (39 men, 6 women); mean age at injury, 26 yrs; mean time since injury, 11 yrs.

INTERVENTION

Repetitive passive movements of standardized range of motion in three different body positions, performed by two motorized tables.

MAIN OUTCOME MEASURES

VAS ratings of spasticity, every other hour when awake, and of movement-provoked spasticity, rated before and after each treatment session, and MAS ratings of movement-provoked spasticity, before and after each treatment session.

RESULTS

The spasticity of cervical SCI subjects fluctuated significantly (p < .05) during the day, unlike the spasticity of thoracic SCI subjects. Immediately after intervention with passive movements, spasticity ratings in thoracic motor complete SCI patients decreased by 11 to 14 mm (90%, p < .001) as self-rated on VAS and by 1 to 2 grades (50%, p < .001) as measured with MAS. A 30% (p < .018) decrease in VAS values of intrinsic pattern of spasticity was maintained over time when treatment was given regularly and was maintained for at least 1 week after discontinuation of treatment. VAS ratings correlated significantly with MAS ratings (r = .44 to .62, p < .001).

CONCLUSION

Repetitive passive movement intervention decreased spasticity when performed regularly, as assessed by VAS and MAS ratings. VAS and MAS ratings were significantly correlated. It is recommended that SCI patients repeatedly rate their spasticity to establish a baseline before and to track changes after interventions aimed at reducing spasticity. The time of day when spasticity is measured seems more important in cervically injured individuals, because of their more pronounced intrinsic fluctuations.

Gabapentin effect on spasticity in multiple sclerosis: a placebo-controlled, randomized trial

OBJECTIVE

To investigate the effect of gabapentin on subject self-report and physician-administered spasticity scales in individuals with multiple sclerosis.

DESIGN

Prospective, double-masked, placebo-controlled, crossover design.

SETTING

The Multiple Sclerosis Center at the Denver Veterans Affairs Medical Center.

INTERVENTION

Subjects were titrated to either 900 mg gabapentin orally three times a day or placebo over a 6-day period. Subjects underwent a 14-day washout and then were crossed over. No other changes were made to their medication regimen.

MAIN OUTCOME MEASURES

The outcome measures were divided into two categories: subject self-report scales physician-administered scales. Subject self-report scales included the spasm frequency scale, spasm severity scale, interference with function scale, painful spasm scale, and global assessment scale. Physician-administered scales included the Modified Ashworth Scale, clonus scale, deep tendon reflexes, plantar stimulation response, and the Kurtzke Expanded Disability Status (EDSS) Scale. Digit Span and Digit Symbol subtests of the WAIS-R Intelligence Scale were administered to assess for possible impaired concentration. The Fatigue Impact Scale was administered to assess for changes in fatigue. The adjective generation technique was administered to assess for alterations in mood.

RESULTS

A statistically significant reduction in the impairment of spasticity was found in the gabapentin-treated subjects compared with placebo as measured by the self-report scales of the spasm severity scale, interference with function scale, painful spasm scale, and global assessment scale and by the physician-administered scales of the Modified Ashworth and plantar stimulation response. No significant difference was noted in the Digit Span, Digit Symbol, adjective generation technique, and EDSS.

CONCLUSION

Gabapentin reduces the impairment of spasticity, compared with placebo, without the side effects of worsening concentration and fatigue.

Pharmacological interventions for spasticity following spinal cord injury

BACKGROUND

Spasticity is a major health problem for patients with a spinal cord injury (SCI) that limits patients' mobility and affects independence in activities of daily living and work. Spasticity may also cause pain, loss of range of motion, contractures, sleep disorders and impair ambulation in patients with an incomplete lesion. The effectiveness of available drugs is still uncertain and they may cause adverse effects. Assessing what works in this area is complicated by the lack of valid and reliable measurement tools. The aim of this systematic review is to critically appraise and summarise existing information of the effectiveness of available treatments and to identify areas where further research is needed.

OBJECTIVES

To assess the effectiveness and safety of Baclofen, Dantrolene, Tizanidine and any other drugs for the treatment of long term spasticity in SCI patients as well as the effectiveness and safety of different routes of administration of Baclofen.

SEARCH STRATEGY

We searched the Injuries Group specialised register, the Cochrane Controlled Trials Register, MEDLINE, EMBASE and CINHALH up to 1998. Drug companies and experts active in the area were also contacted.

SELECTION CRITERIA

All parallel and crossover RCTs including spinal cord injury patients complaining of "severe spasticity". Studies where less than 50% of patients had a spinal cord injury were excluded.

DATA COLLECTION AND ANALYSIS

Methodological quality of studies (allocation concealment, blinding, patients characteristics, inclusion and exclusion criteria; interventions; outcomes; lost to follow up) was independently assessed by two investigators. The heterogeneity among studies did not allow quantitative combination of results.

MAIN RESULTS

Nine out of 53 studies met the inclusion criteria. Study design was: 8 cross over, 1 parallel-group trial. Two studies (14 SCI patients), showed a significant effect of intrathecal baclofen in reducing spasticity (Ashworth Score and ADL performances), compared to placebo, without any side effect. The study comparing tizanidine to placebo (118 SCI patients) showed a significant effect of tizanidine in improving Ashworth Score but not in ADL performances. Tizanidine group reported significant rates of adverse effects (drowsiness, xerostomia). For the other drugs (Gabapentine, Clonidine, Diazepam, Amytal and oral Baclofen ) the results do not provide evidence for a clinical significant effectiveness.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to assist clinicians in a rational approach to antispastic treatment for SCI. Further research is urgently needed to improve the scientific basis of patient care.

Spasticity after traumatic spinal cord injury: nature, severity, and location

OBJECTIVE

To assess spasticity in a prevalence population of persons with traumatic spinal cord injury (SCI), and determine the degree of correspondence between self-reported spasticity and investigator-elicited spasticity using the modified Ashworth scale.

DESIGN

Survey of a near total (88%) prevalence population.

SETTING

Outpatient clinic of a university hospital.

PATIENTS

A total of 354 individuals with SCI.

MAIN OUTCOME MEASURES

The survey includes self-reported symptoms, neurologic examination (American Spinal Injury Association [ASIA] classification), physical therapy examination, range of motion (ROM), and complications.

RESULTS

Presence of problematic spasticity was significantly correlated with cervical incomplete (ASIA B-D) injury. Reports of beneficial effects of spasticity were significantly less common in women. Self-reported problematic spasticity was significantly correlated with extensor spasticity. Spasticity was elicitable by movement provocation in 60% of the patients reporting spasticity. Significant correlations were found between elicitable spasticity and limited ROM.

CONCLUSION

Flexion, extension, and abduction movements performed with the patient placed in a standardized supine test position are suitable both for test of ROM and degree of spasticity. Spasticity was not elicitable by movement provocation on physical examination in 40% of the patients who reported spasticity, thus indicating that the patient's self-report is an important complement to the clinical assessment. A significant association between spasticity and contractures (reduced ROM) was seen.

Symptomatic therapies of multiple sclerosis

Symptom management is the assessment and treatment of the manifestations of multiple sclerosis (MS). Optimal treatment includes patient education, rehabilitation, counseling, and sometimes medical or surgical therapy. A multi-disciplinary treatment team is usually required to provide the wide range of services necessary to manage MS symptoms. This article will review the medical and surgical options used in the management of primary MS symptoms.

3-substituted GABA analogs with central nervous system activity: a review

Gabapentin and Pregabalin are both 3-alkylated gamma-amino butyric acid (GABA) analogs. Gabapentin was designed as a lipophilic GABA analog and was first synthesized as a potential anticonvulsant and was launched in 1994 as add-on therapy for the treatment of epilepsy. In this review the discovery and development of gabapentin as an anticonvulsant are discussed. During human trials and while in clinical use, it became apparent that gabapentin induced some other potentially useful therapeutic effects in chronic pain states and behavioral disorders. A review of animal and clinical data relating to these other potential therapeutic utilities is presented. Pregabalin was identified after an investigation into other 3-substituted GABA analogs. It has since been shown to have a similar pharmacological profile to gabapentin with greater potency in preclinical models of pain and epilepsy. Studies of the mechanism(s) of action of these compounds are discussed. Work towards identifying new analogs of both gabapentin and pregabalin is also reviewed.

Gabapentin for relief of upper motor neuron symptoms in multiple sclerosis

OBJECTIVE

To examine the efficacy of gabapentin in the treatment of spasticity and painful muscle spasms in patients with multiple sclerosis.

DESIGN

Double-blind, placebo-controlled crossover study.

SETTING

Free-standing, 93-bed, university-affiliated rehabilitation hospital.

PARTICIPANTS

There were 15 patients between the ages of 18 and 50 who had laboratory-supported definite multiple sclerosis with spasticity and leg cramps severe enough to interfere with daily activities, including sleep.

INTERVENTION

The patients received the placebo or 400mg gabapentin orally three times a day for 48 hours with an 11-day washout period. If the patients were on currently accepted modes of therapy, including oral baclofen, their current medication was not changed.

MAIN OUTCOME MEASURES

The outcome measures were Visual Faces Scale rating, Kurtzke Disability Scale, quantitative surface electromyography, Ashworth Scale, presence or absence of clonus in response to rapid ankle dorsiflexion and wrist extension, presence or absence of reflex withdrawal in response to nailbed pressure to the first finger, and assessment of Babinski response.

RESULTS

Statistically significant improvements for the gabapentin treated patients were found in the Ashworth Scale, Visual Faces Scale, and Kurtzke Disability Scale.

CONCLUSIONS

At a dose of 400mg orally three times a day, gabapentin may be of value in the treatment of the spasticity and painful muscle cramping experienced by patients with multiple sclerosis.