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MULTIPLE SCLEROSIS
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BMJ
2001;323:870 ( 13 October ) Withdrawal of baclofen may cause acute confusion in elderly patientsEDITOR
An 82 year old man with left ventricular dysfunction and gout was admitted for deteriorating renal function. On admission he was taking lisinopril and frusemide, which were reduced; naproxen, which was stopped; allopurinol; and baclofen 20 mg three times daily. As no reason could be found for his baclofen treatment the dose was halved, and then stopped 10 days later. Next day the patient had visual hallucinations with confusion and agitation requiring sedation with diazepam. He was afebrile with normal inflammatory markers. Computed tomography showed only cerebral atrophy. Before a lumbar puncture could be performed to exclude encephalitis, baclofen was reintroduced, with complete resolution of neuropsychiatric symptoms within 48 hours. Baclofen is a derivative of
Baclofen has a half life of 3-4 hours, with 85% being renally excreted within 24 hours. Thus symptoms of withdrawal tend to occur rapidly. Withdrawal of oral baclofen results in neuropsychiatric symptoms as described above (anxiety, delusions, auditory and visual hallucinations) and new onset seizure activity.2 Withdrawal of intrathecal baclofen, however, causes more serious systemic side effects (increased spasticity, hyperthermia, rhabdomyolysis, renal failure, and disseminated intravascular coagulopathy). 3 4 This resulted in death in one report.4 Treatment is supportive, with reintroduction of baclofen often leading to the resolution of symptoms within 24-48 hours. Dantrolene has been used successfully to treat one resistant case.5 Caution should be exercised when reducing or stopping long term baclofen
treatment. The Committee on Safety of Medicines recommends tapering
the dose over 1-2 weeks, or more slowly if symptoms occur. |
Ratnayaka et al have
reported neonatal convulsions after withdrawal of baclofen.
-aminobutyric
acid, exerting an inhibitory effect on spinal reflexes and reducing excessive
tone. Oral baclofen is commonly used to treat spasticity of spinal
origin, but 25-35% of cases are refractory to treatment or have
considerable depression of the central nervous system, so that
intrathecal administration is necessary. Baclofen is also commonly
used to treat spasticity occurring as a result of stroke.