A new agent for the control of spasticity

Clinical Appraisal of Baclofen in the Adult Stroke Patient

Little work, using comparable protocols, has been done using baclofen in the management of patients following stroke. Extrapolation from trials in patients with spasticity and other spinal or cerebral pathology is not justified, partly because the symptoms and signs of stroke vary. However the reliable work which has been done indicates that baclofen is superior to diazepam in reducing spasticity and flexor spasms and in improving mobility and self help. Baclofen is as effective as diazepam in relieving clonus and pain associated with spasticity. The effect on bladder function is not reliably known. Unwanted effects are few and not serious: drowsiness is the most common, but occurs more frequently and noticeably with diazepam. Side effects were more likely to occur with doses in excess of 60 mg/day, if dose increments were made too rapidly and in patients with Parkinson's disease. More work is required with baclofen in managing patients after stroke.

The Effect of Baclofen on the Gait of Hemiplegic Children Assessed by Means of Polarised Light Goniometry

Gait was assessed by polarised light goniometry in 15 hemiplegic children aged 4−15 years. After initial clinical and goniometric assessment, baclofen 5−10 mg/day was started and increased over 4−6 weeks to a dose of 1−1.5 mg/kg/day. Assessment was repeated one week later. A statistically significant decrease in hip and knee flexion at the ‘toe-off’ phase of the gait cycle was found in both legs. Of the nine children who showed most change in goniometric assessment, five showed an obvious clinical improvement, two a slight improvement, one no change and one child's gait deteriorated. Of six children with minimal or no change goniometrically, four showed no change clinically, one minimal clinical improvement and one a deterioration clinically. Side effects included transient sedation (seven children), concentration difficulty (one child), behaviour disturbance (1 child) and nocturnal enuresis (three children). We concluded that although baclofen causes functional improvement in some hemiplegic children, its use should be carefully supervised in view of possible side effects and possible deterioration in gait.

Validated Method for the Quantification of Baclofen in Human Plasma Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry

A highly sensitive and fully validated method was developed for the quantification of baclofen in human plasma. After adjusting the pH of the plasma samples using a phosphate buffer solution (pH 4), baclofen was purified using mixed mode (C8/cation exchange) solid-phase extraction (SPE) cartridges. Endogenous water-soluble compounds and lipids were removed from the cartridges before the samples were eluted and concentrated. The samples were analyzed using triple-quadrupole liquid chromatography-tandem mass spectrometry (LC-MS-MS) with triggered dynamic multiple reaction monitoring mode for simultaneous quantification and confirmation. The assay was linear from 25 to 1,000 ng/mL (r(2) > 0.999; n = 6). Intraday (n = 6) and interday (n = 15) imprecisions (% relative standard deviation) were <5%, and the average recovery was 30%. The limit of detection of the method was 5 ng/mL, and the limit of quantification was 25 ng/mL. Plasma samples from healthy male volunteers (n = 9, median age: 22) given two single oral doses of baclofen (10 and 60 mg) on nonconsecutive days were analyzed to demonstrate method applicability.

A Comparison of Methods to Assess the Excitability of Lower Motoneurones

The purpose of this investigation was to compare three methods of assessing the excitability of lower motoneurones—TA-reflex, H-reflex and F-wave—in 120 patients with spastic hemiparesis following a stroke. The H-reflex was recorded from the soleus muscle after submaximal electrostimulation of the tibial nerve. The T-Achilles (TA) reflex was recorded from the soleus muscle after percussion of the Achilles tendon. The F-wave was recorded in the distal limb muscles after supramaximal electrostimulation of the median, ulnar, fibular and tibial nerves. The patient’s healthy side was used as a control. The TA-reflex, H-reflex and F-wave showed increased amplitudes on the spastic side. All amplitude ratios: TA/M, H/M, Fmax/M and Fmean/M were increased. The H-reflex thresholds were decreased. The F-wave duration, persistence and number of phases were also increased on the spastic side. Despite clinically decreased muscle tone, there were no changes in TA or H-reflex parameters after treatment. On the other hand, F-wave parameters tended to normalize after treatment in all groups. In conclusion, the F-wave is a more sensitive method than the TA and H-reflexes in assessing the excitability of the lower motoneurone.

Oral baclofen in children with cerebral palsy: a double-blind cross-over pilot study

AIM

To assess the effectiveness of oral baclofen in reducing spasticity and improving function in children with cerebral palsy.

METHODS

A double-blind, randomised cross-over pilot study of oral baclofen versus placebo. Assessment tools included the Goal Attainment Scale, Pediatric Evaluation of Disability Inventory, Modified Tardieu Scale and parent questionnaire.

RESULTS

Fifteen children with mean age 7.4 years (SD=2.7 years) and spastic or spastic/dystonic quadriplegia (Gross Motor Function Classification System Level IV or V) were enrolled. Children scored significantly better on the Goal Attainment Scale with baclofen compared with placebo (F(1,13)=4.5, P=0.05). There was no significant difference between baclofen and placebo for the Pediatric Evaluation of Disability Inventory or Modified Tardieu Scale. Parent questionnaire results are described.

CONCLUSION

This pilot study demonstrates that oral baclofen has an effect beyond placebo in improving goal-oriented tasks, such as transfers, in children with spastic quadriplegic cerebral palsy.

Prolonged anti-spasticity effects of bolus intrathecal baclofen

Anecdotal patient reports have suggested prolonged benefit from the initial bolus dose of intrathecal baclofen (bolus ITB) that have not been evident on the Modified Ashworth Scale (MAS). This case study assessed this effect utilizing surface electromyography (SEMG) as an adjunct to clinical observations. Overall, SEMG recordings were consistent with MAS findings. However, SEMG also revealed a marked and persisting reduction in abnormal muscle activity for 96 hours post-bolus ITB, well beyond the pharmacological washout period of baclofen in the CSF.

Human GABA(B)R genomic structure: evidence for splice variants in GABA(B)R1 but not GABA(B)R2

The type B gamma-aminobutryic acid receptor (GABA(B)R) is a G protein coupled receptor that mediates slow pre- and post-synaptic inhibition in the nervous system. We find that the human GABA(B)R2 gene spans greater than 350 kb and contains 2.8 kb of coding region in 19 exons. The overall similarity in genomic structure with regard to conservation of intron position and exon size between human or Drosophila GABA(B)R1 and GABA(B)R2 genes suggests a common ancestral origin. Multiple transcripts GABA(B)R1a-c and GABA(B)R2a-c have been described and alternative splicing has been proposed to result in GABA(B)R1c, GABA(B)R2b and GABA(B)R2c. The results described here provide support for the existence of GABA(B)R1c but not for GABA(B)R2b and GABA(B)R2c. Splice junctions present in the GABA(B)R1 gene sequence are consistent with the formation of GABA(B)R1c by exon skipping of one sushi domain module. The GABA(B)R2 gene lacks canonical splice junctions for the reported variants. Consistent with this, RNA analysis demonstrates the presence of GABA(B)R1c and GABA(B)R2 transcripts in fetal and adult human brain RNA but GABA(B)R2b and GABA(B)R2c transcripts are not detected. These results provide insight into the evolution and transcript diversity of the mammalian GABA(B)R genes.

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.

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.

Chronic intrathecal delivery of baclofen by a programmable pump for the treatment of severe spasticity

The aim of this study was to determine the efficacy, safety, and cost-effectiveness of intrathecal baclofen delivered by a programmable pump for the chronic treatment of severe spasticity. Sixty-six patients with severe spasticity of spinal cord origin that was refractory to oral baclofen or who experienced intolerable side effects with this form of the drug were screened. The first nine participated in a double-blinded, randomized, placebo (normal saline)-controlled trial to determine response to a bolus dose of intrathecal baclofen. Subsequent patients were enrolled in an open-label treatment protocol without a placebo trial. All passed the screening, and the pump was implanted in 59 patients. Spasticity scores and medical costs before and after surgery were analyzed. In all patients, the mean Ashworth score for rigidity decreased from 4.3 preoperatively to 1.4 (p < 0.0005) with use of intrathecal baclofen. The spasm frequency score decreased from a mean of 3.6 to 0.5 (p < 0.0005). Activities of daily living, sleep, and skin integrity improved, and pain was eradicated in some. Constipation occurred in six patients. A reduction in dosage was necessitated by muscular hypotonia in three ambulatory patients, areflexic bladder and urinary retention in three others, and nausea, dizziness, and drowsiness in one. Catheter-related problems occurred 19 times in 15 patients. One pump was explanted because of infection in the pump pocket, and one was removed after it eroded through the skin. There were no pump failures. The use of intrathecal baclofen resulted in a decrease in the average length of subsequent hospitalizations. It is concluded that intrathecal baclofen delivered by an implanted programmable pump is a safe, effective, and cost-efficient method for treatment of severe intractable spinal spasticity.

Baclofen, a selective GABAB receptor agonist, dose-dependently impairs spatial learning in rats

The present investigation assessed the effects of the selective GABAB receptor agonist baclofen (1, 3, and 6 mg/kg) on spatial learning in the Morris water maze, an aversively motivated spatial learning task. Potential anxiolytic and sedative effects of baclofen were also assessed in an open field. Baclofen dose-dependently reduced locomotion in the open field but had little effect on thigmotaxia (anxiety). In the water maze, baclofen dose-dependently impaired spatial learning and reduced swim speed. During the probe trial given after training, only rats treated with the highest dose of baclofen (6 mg/kg) failed to show a bias for the correct quadrant. Following four additional retraining trials, a second drug-reversal probe trial was given and it was found that rats switched from saline to the highest dose of baclofen (6 mg/kg) showed a bias for the correct quadrant, as did rats switched from the two lowest doses of baclofen (1 and 3 mg/kg) to saline. Rats switched from the highest dose of baclofen (6 mg/kg) to saline failed to show a quadrant bias. Performance on a visible platform task was not impaired by baclofen at any dose. Together these results suggest that baclofen resembles GABAA agonists/positive modulators in that it impairs spatial learning, but not performance of a previously acquired escape response; but differs in that it does not reduce thigmotaxia (anxiety). Potential mechanisms by which baclofen impairs mnemonic processes are discussed.

Comparison of the antinociceptive and antispastic action of (-)-baclofen after systemic and intrathecal administration in intact, acute and chronic spinal rats

Baclofen is particularly effective in treating spasticity of spinal origin in humans. However, most investigations of this drug in animals have only assessed its antinociceptive effect, presumably because of the difficulty in developing animal models of spasticity. This study attempted to evaluate both, the antinociceptive and antispastic action of (-)-baclofen (the more active enantiomer) by incorporating the chronic spinal preparation, in which spasticity gradually develops following spinal transection. Separate groups of intact, acute (1 day) or chronic (20-25 days) spinal rats were pretested on the nociceptive tail-flick (TF) assay prior to either subcutaneous (SC; 1-30 mg/kg) or intrathecal (IT; 0.1-12 micrograms) injection of (-)-baclofen and retested at specific post-injection intervals. Hindlimb spasticity was elicited in chronic spinal rats by mechanical stimulation to the abdomen. Because the clinical use of baclofen generally involves chronic administration, both responses were tested for 3 successive days to assess tolerance. Results confirmed the analgesic effect of SC and IT (-)-baclofen in intact rats. As previously reported, the antinociceptive effect of IT (-)-baclofen was increased in acute spinal rats. However, three weeks after spinalization there was a profound decrease in this response. In contrast, antinociception produced by SC (-)-baclofen was reduced in acute and chronic spinal rats compared to intact animals; but there was no difference between the acute and chronic conditions. In spite of this differential decrease in antinociception after IT, relative to SC, administration, both routes of administration produced an antispastic effect in chronic spinal rats. There was no antinociceptive tolerance to SC administration and only minimal tolerance to IT (-)-baclofen (in intact rats); the antispastic effect did not become tolerant. A peripheral action might explain the dichotomy between SC and IT (-)-baclofen in regard to antinociception. However, further research is needed to determine why both routes of administration were effective against spasticity while only SC (-)-baclofen retained an antinociceptive action in chronic spinal rats.

Intrathecal baclofen therapy for adults with spinal spasticity: therapeutic efficacy and effect on hospital admissions

A prospective trial to demonstrate the efficacy of intrathecal baclofen therapy by implanted pump for adults with spasticity due to spinal cord injury or multiple sclerosis was initiated in our hospital. Of the 140 patients assessed, 7 met the following criteria for inclusion in the study: a modified Ashworth score > 3, a spasm frequency score > 2, and an inadequate response to oral anti-spasticity drugs, (i.e., baclofen, clonidine and cyproheptadine). All patients responded to intrathecal bolus injection of baclofen in the double blind, placebo-controlled screening phase (mean bolus dose = 42.8 micrograms). Programmable Medtronic pumps were implanted in 4 patients while 3 patients received non-programmable Infusaid pumps. Post-implantation, a marked decrease in spasticity occurred with a significant reduction of the Ashworth score (mean = 1.8, p < .005), a reduced spasm score (mean = 0.8, p < .005), and an improved leg swing in the pendulum test. These effects were maintained during a follow-up of 24-41 months (average infusion dose = 218.7 micrograms/day). The gross cost-savings due to reduced hospitalizations related to spasticity was calculated by comparing the cost for the two year period before pump implantation to the same period after treatment for 6 of the 7 patients. The cost of in-hospital implantation as well as the cost of the pumps were deducted from the gross savings. There was a net cost-saving of $153,120. Our findings agree with the reported efficacy and safety of intrathecal baclofen treatment, and illustrate the cost-effectiveness of this treatment.

Mechanisms of tizanidine action on spasticity

This investigation estimated the mechanisms of tizanidine action on spasticity using a battery of neurophysiological methods. Thirty patients with old post-stroke spastic hemiparesis took part in the investigation. They were treated with tizanidine-mean daily dose 15.8 +/- 5.6 mg for a mean of 23.3 +/- 4.8 days. A questionnaire for assessment of subjective improvement after treatment used a 5-point scale. For standardization of the neurological examination 5-point scales were used to assess muscle tone, muscle force and tendon reflexes. A battery of neurophysiological methods was used to analyze different mechanisms of spasticity: for alpha motoneuron excitability--the F wave parameters; for presynaptic inhibition--the ratio of H reflex amplitudes before and after vibration of the achilles tendon (Hvibr/Hmax); for common interneuron activity--the flexor reflex parameters. Our results revealed that tizanidine reduces spastically increased muscle tone, but has no influence on muscle force, tendon reflexes, Babinski sign and ankle clonus. Tizanidine is supposed to act by increasing the presynaptic inhibition and decreasing of alpha motoneuron excitability. When spasticity has decreased presynaptic inhibition and increased motoneuron excitability, it is better to treat with tizanidine.

Intrathecal baclofen for severe spasticity secondary to spinal cord injury

OBJECTIVE

To evaluate the use of intrathecal baclofen for the treatment of muscle spasticity in patients with spinal cord injury.

DATA SOURCES

A MEDLINE search was used to identify relevant and pertinent literature. Information was obtained from open-label clinical trials, abstracts, conference proceedings, and review articles. Index terms in the search included baclofen, spasticity, intrathecal drug infusion, spinal cord disease, and neurosurgery.

DATA EXTRACTION

Studies were selected for review if they evaluated intrathecal baclofen in patients with spinal cord injury. Emphasis was placed on human studies published in the English language. Trials were reviewed by dosage regimen, therapeutic response, adverse effects, and complications.

DATA SYNTHESIS

Thus far, intrathecal baclofen administration shows promise in the treatment of spasticity resulting from spinal cord trauma. Few complications and adverse effects have been reported.

CONCLUSIONS

Muscle spasms and spasticity constitute a significant problem in spinal cord injuries, interfering with rehabilitation and leading to inconveniences and complications in these patients. Oral baclofen is the drug of choice for spasticity due to spinal cord trauma. It often is ineffective, however, because of the large dosages required to cross the blood-brain barrier and the subsequent appearance of central nervous system adverse effects. These adverse effects are not tolerated by many patients. Intrathecally administered baclofen has been approved by the Food and Drug Administration (FDA) for the treatment of spasticity in patients with spinal cord injury who are refractory to or cannot tolerate oral baclofen. It is intended for use only in implantable pumps approved by the FDA for the administration of baclofen into the intrathecal space. Intrathecal administration achieves high concentrations in the spinal cord with small dosages, thus reducing the incidence of central nervous system adverse effects. To date, approximately 350 patients with spinal cord injury have been treated with intrathecal baclofen. Reductions in spasticity have been demonstrated in both open-label and placebo-controlled trials. Patients also often make substantial gains in activities of daily living. Few adverse effects and complications have been reported. However, tolerance to the clinical effects of intrathecal baclofen has been reported. Further studies are needed to determine specific patient populations that may benefit most from intrathecal baclofen administration. Individual dosage ranges and follow-up care also need to be defined more completely. In addition, the question of whether tolerance detracts from long-term clinical benefits with intrathecal baclofen needs to be addressed.

Mechanisms of baclofen action on spasticity

This investigation estimated the mechanisms of baclofen action on spasticity using a battery of electromyographic methods. Thirty patients with old post-stroke spastic hemiparesis took part in the investigation. They were treated with baclofen-mean daily dose 54.3 alpha 11.6 mg for a mean of 26.3 alpha 4.9 days. A questionnaire for assessment of subjective improvement after treatment used a 5-point scale. For standardization of the neurological examination 5-point scales were used to assess muscle tone, muscle force and tendon reflexes. A battery of electromyographic methods was used to analyse different mechanisms of spasticity: for alpha motoneurone activity--the F wave parameters; for gamma motoneurone activity--the T/H reflex amplitude ratio; for presynaptic inhibition--the ratio of H reflex amplitudes before and after vibration on the achilles tendon (Hvibr./Hmax); for common interneurone activity--the flexor reflex parameters. Our results revealed that baclofen reduces spastically increased muscle tone and Babinski sign. It has no influence on muscle force, tendon reflexes and ankle clonus. Baclofen acts by normalizing the altered interneurone activity and decreasing of alpha motoneurone activity. When spasticity has altered interneurone activity and increased motoneurone activity, it is better to treat with baclofen.

A comparative study of methods for estimation of presynaptic inhibition

The influence of vibration on the H-reflex and on the tendon reflex amplitudes was compared and the efficacy of both methods for the assessment of the presynaptic inhibition was studied. One hundred and twenty patients with post-stroke spastic hemiparesis were investigated. Muscle tone, muscle force and tendon reflexes were assessed. The H-reflex and the Achilles tendon reflex (TA) were recorded under identical experimental conditions. Vibration at a frequency of 100 Hz and an amplitude of 2 mm was applied to the TA. Just after vibration the maximal amplitudes of both reflexes were measured. The ratios of reflex amplitudes after vibration to normal maximal reflex amplitudes (Hvibr/Hmax and TAvibr/TAmax) were evaluated. In all patients with hemiparesis the healthy side was used as a control. Our results revealed significantly increased amplitude ratios on the spastic side. Hence it is concluded that presynaptic inhibition is decreased in spasticity. The amplitude ratios on the healthy and the spastic side were consistent. There was good positive correlation between Hvibr/Hmax and TAvibr/TAmax ratios, suggesting that they provide similar and reliable estimates of presynaptic inhibition.

Acute transient cerebral intoxication induced by low doses of baclofen

We report a case of acute transient encephalopathy with confusion, drowsiness, myoclonic jerks, periodic triphasic sharp wave EEG patterns induced by low doses of baclofen. We discuss the pathogenesis and the differential diagnosis from the subacute spongiform encephalopathy of sudden onset.

The various types of neurogenic bladder dysfunction: an update of current therapeutic concepts

Increased experience with treatment strategies developed during the last 10 years in the field of neurourology justifies an update of current therapeutic concepts. Based on a rather simple, but clinically useful, classification of detrusor-sphincter dysfunction the therapeutic concepts now available for four prototypes of detrusor-sphincter dysfunction are discussed. (1) For the combination of a hyperreflexive detrusor with a hyperreflexive (spastic) sphincter, characteristic for the reflex- and the uninhibited neuropathic bladder, detrusor-sphincter dyssynergia (DSD) is still the greatest problem, and transurethral sphincterotomy is the method of choice if this situation cannot otherwise be managed. One concept is to convert detrusor hyperreflexia into hyporeflexia by adequate pharmacotherapy, which is nowadays available, and to assist or to accomplish bladder emptying by clean intermittent (self-) catheterisation (CIC) with the advantage of dry intervals in between. Japanese colleagues recommend bladder overdistension during the spinal shock phase to achieve detrusor hyporeflexia, but this procedure is rather decisive at an early stage of the disability, leaving the detrusor no chance for further rehabilitation. Another possibility is rhizotomy of the sacral posterior roots to eliminate detrusor hyperreflexia, and the simultaneous implantation of a sacral anterior root stimulator (Brindley) to achieve electrically induced micturition. From our personal experience with 12 patients this concept is ideal for female patients with unbalanced reflex bladder and otherwise uncontrollable reflex incontinence. (2) The combination of a weak detrusor with a spastic sphincter is a clear indication for CIC, as the bladder is emptied regularly, and due to the spastic sphincter, the patient stays continent as long as controlled fluid intake prohibits overflow incontinence. The implantation of an anterior sacral root stimulator is an alternative approach provided that at least weak reflex detrusor contractions are present. (3) With the combination of an areflexive or hyporeflexive detrusor and a flaccid pelvic floor, passive voiding by abdominal straining or by the Credé manoeuvre is usually recommended, but should be replaced by CIC if this mechanism of bladder emptying creates unphysiological high and dangerous intravesical pressures, or if vesico-uretero-renal reflux is present. Neurogenic urinary stress incontinence is usually associated with this type of lesion and can be successfully treated by the implantation of an artificial urinary sphincter (Scott). However in two thirds of the patients with neurogenic bladder dysfunction, additional, usually operative treatment is necessary to meet the criteria for implantation. Moreover, a 30% rate of repair operations must be accepted by patients, but is becoming less frequently required with an improved design of the device.(ABSTRACT TRUNCATED AT 400 WORDS)

Intrathecal baclofen for long-term treatment of spasticity: a multi-centre study

Twenty eight patients with severe, intractable spasticity have been treated by chronic intrathecal administration of baclofen. An implantable programmable drug-administration-device (DAD) was used with a permanent intrathecal catheter. Infusion of 50 to 800 micrograms/day of baclofen completely abolished spasticity. Follow-up was up to two years. Therapeutic effect was documented by clinical assessment of tone, spasms and reflexes and by electrophysiological recordings of mono- and polysynaptic reflex activity. Complications and untoward side-effects of the procedure were few. This procedure is recommended for spasticity of spinal origin refractory to physiotherapy and oral medication. It is a preferable alternative to ablative surgical intervention.

Implanted pump systems for treatment of spasticity

In about one third of patients with violent spasticity due to spinal trauma, multiple sclerosis, and diffuse brain injury adequate control with oral antispastic medication cannot be achieved and successful rehabilitation is severely handicapped. In the past these patients were subjected to destructive chemical procedures or extensive surgery. The authors present the results of management of uncontrollable spasticity by means of continuous intrathecal administration of baclofen with a totally implantable gas driven pump system (Infusaid). 30 patients were treated between June 1985 and January. 1987. The main indication was incapacitating spasticity resistant to oral treatment with baclofen and caused by spinal cord injury or lesion (11 patients), multiple sclerosis (11 patients), infantile cerebral palsy (3 patients) and cerebral injury, hypoxia or ischaemia (5 patients). Clinical assessment included spasticity scores, integrated electromyography (Iemg) and motography. Effective control for spasticity with mean reduction of Iemg by 55%, decrease of Ashworth's score from 3 to 0 and improvement of life quality was obtained in all patients with daily dose of 10-800 micrograms of Baclofen. Voluntary resting motoricity was not impaired and there were no untoward central side effects. The excellent effect of intrathecal baclofen in comparison with oral therapy is explained by local, spinal GABAergic inhibitory action of the drug which is delivered directly into spinal subarachnoid space. Dose finding and dose adjustment is performed prior to pump implantation by intermittent injections into a subcutaneous port. The complications of the procedure were minor (catheter displacement, disconnection) and easily correctable.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of intrathecal baclofen on electrical muscle activity in spasticity

The efficacy of intrathecally administered baclofen was demonstrated in three patients with different types of muscular hypertonia (supraspinal rigidity, spasms shortly after spinal trauma, spasms for many years induced by multiple sclerosis) using integrated electromyography. Reduction of muscular electrical activity was accompanied by clinical improvement during long-term infusion via an implanted pump. The three patients have been observed for more than 1 year, during which time the antispastic activity of intrathecally infused baclofen has remained stable. Intrathecal application of baclofen may be considered as a possible alternative to surgery.

Overdose of cyclobenzaprine, the tricyclic muscle relaxant

A case of cyclobenzaprine (Flexeril) overdose in a 31-year-old woman is presented. The treatment rendered was analogous to treatment protocols implemented for tricyclic overdose. A review of the pharmacology of cyclobenzaprine, as well as the management of patients who overdose on this drug, is presented.

Reversible electroencephalogram changes associated with administration of baclofen in a quadriplegic patient: case report

We present the case of a spastic quadriplegic who developed mental symptoms which resolved when his Baclofen was discontinued. Of interest was the presence of EEG abnormalities similar to those described in cats receiving this drug. These abnormalities, previously unreported in humans, resolved upon discontinuing Baclofen therapy.

Cyclobenzaprine overdosage

The clinical findings in three patients who ingested 260-900 mg cyclobenzaprine (Flexeril) consisted of delayed onset and long duration of anticholinergic symptomatology. In two of these patients, symptoms responded to treatment with physostigmine. The third patient recovered without specific therapy. Despite its structural similarity to amitriptyline, cyclobenzaprine overdosage did not result in coma, seizures, or cardiac toxicity. The pharmacological properties of cyclobenzaprine may account for the observed toxicity.

The effects of baclofen on gamma motoneurones supplying gastrocnemius muscle in the rabbit

The effect of baclofen on gamma motoneurones supplying gastrocnemius medialis muscle in the rabbit has been investigated. Baclofen was found to decrease the frequency of firing of tonic gamma motoneurones, and in some cells to inhibit the tonic discharge altogether. Baclofen also increased the regularity of tonic gamma motoneurone discharge. The drug was found to raise the threshold for firing of gamma motoneurones in response to electrical stimulation of the sural nerve, indicating a depression of reflex transmission between the sural nerve and the motoneurones. The results are discussed and brief consideration given to the possible consequences of these results for the action of the drug in human spasticity.

Concentrations of baclofen in serum and breast milk from a lactating woman

A lactating woman with spastic paraplegia was given 94 mumol (20 mg) of baclofen orally to study the transport of the drug into breast milk. The concentration of baclofen in serum and milk was determined with a gas chromatographic--mass spectrometric method. The elimination curves in serum and milk showed a similar course, the elimination from milk being delayed about 3 h relative to serum. The total amount of baclofen excreted in the milk during 24 h was about one thousandth of the ingested dose.

The effect of decerebrate rigidity on the intracranial pressure: an experimental study

The mechanical effect of acute decerebrate rigidity upon the ICP and the mechanisms underlying the relationship between them have been investigated with experiments performed on 26 cats. It has been shown that: a) Extreme rigidity of the peripheral musculature with or without partial activation of the trunkal muscles produces no change in ICP, b) the simultaneous elevation of the intra-thoracic and intra-abdominal pressures is the factor primarily operative in raising and maintaining the elevated ICP, c) when cerebrovascular homeostasis is already defective a subsidiary but not unimportant role is played by the elevation of the systemic arterial pressure, d) under conditions of normal brain elastance mild and short-lasting spasms produce no effect on the ICP. In an animal, however, in which the brain elastance had been increased by inflating a small air-filled balloon, similar spasms produced a marked increase in ICP.

Effect of baclofen and dantrolene on bladder stimulator-induced detrusor-sphincter dyssynergia in dogs

The effect of baclofen (Lioresal) and dantrolene (Dantrium) on bladder stimulation-induced detrusor-sphincter dyssynergia was studied in normal and chronic T-10 paraplegic dogs. Dantrolene, which depresses skeletal muscle contractility, had little effect on electrically evoked contractions of the urethral sphincter in dogs. Baclofen, which acts centrally by potentiating presynaptic inhibition, depressed the pudendal to pudendal nerve reflex and decreased urethral resistance during bladder stimulation.

[Clinico-quatitative evaluation of the action of Ciba 34.647-Ba on spasticity]

Using the clinical quantification of the neurologic symptomatology the authors made observations and avaliated the action of Ciba 34.647-Ba, a GABA derivative, in 12 patients suffering from spasticity and motor incapacity due to spinal cord lesions. The results are reported emphasizing the effects of the drug on the main components of spasticity (hypertonus, hyperactivity of the deep reflexes, clonus and automatisms). Some theories explaining the mechanism of action of the drug are mentioned. References are made about doses, duration of action, tolerance and side-effects.

Increase in mouse brain dopamine content by baclofen: effects of apomorphine and neuroleptics

Baclofen, like gamma-butyrolactone, causes a dose-dependent increase in the concentration of dopamine in the mouse brain without affecting the content of norepinephrine. This increase is antagonized by apomorphine. Haloperidol but not pimozide counteracts this effect of apomorphine and dose-dependently enhances the increase in brain dopamine produced by baclofen. The results suggest that baclofen reduces impulse flow in dopaminergic neurons in a manner similar to that produced by gamma-butyrolactone.

Evaluation of baclofen (Lioresal) for spasticity in multiple sclerosis

The effect of baclofen on spasticity and muscle spasms was assessed in thirty-five patients with multiple sclerosis. Benefit from reduction of spasticity was obtained in sixteen patients. A higher proportion of patients confined to a wheelchair was helped than ambulant patients, but overall functional improvement was limited. Twenty-one of the thirty-five patients had troublesome spasms and thirteen of them had significant relief on baclofen. Substituting identical dummy tablets confirmed that benefit was attributable to the pharmacological effects of baclofen in ten of the sixteen patients whose spasticity was reduced and in eight of the thirteen whose muscle spasms were relieved. In two of the remainder, benefit appeared to be due to placebo effect, and the others maintained their improvement after stopping the drug.

The drug had to be withdrawn in nine patients because of increased weakness and in ten other patients who had intolerable side effects. The optimum dose of baclofen tolerated ranged from 15 mg to 80 mg daily. The importance of adjusting the dose regime to the requirement of each individual and starting with small doses in multiple sclerosis is emphasized.

A phenothiazine derivative in the treatment of spasticity

The efficacy of a selective fusimotor suppressant, the phenothiazine (+/-)-10-3-dimethylamino-2-methylpropyl)-2-valeroylphenothiazine, has been assessed in a double-blind crossover trail in eight patients suffering from cerebral spasticity and one patient suffering from spinal spasticity. Dosage was 40 mg daily. Independent clinical and electromyographic methods of assessment were used. The active agent produced a small but significant reduction in spasticity, although this was of clinical value in only a few patients. There were few side-effects. It is recommended that further studies using higher dosages be undertaken.