From the FDA Drug Label
DOSAGE AND ADMINISTRATION A single oral dose of 8 mg of tizanidine reduces muscle tone in patients with spasticity for a period of several hours. The FDA drug label does not answer the question.
From the Research
Baclofen should be avoided in patients with End-Stage Renal Disease (ESRD) undergoing dialysis due to the high risk of encephalopathy, and alternative muscle relaxants such as tizanidine should be considered instead. The use of baclofen in patients with ESRD has been associated with a significant risk of encephalopathy, with a study published in 2020 finding that approximately one in 14 patients were hospitalized with encephalopathy shortly after starting baclofen 1. This study, which used linked healthcare databases to conduct a population-based cohort study of older adults receiving maintenance dialysis in Ontario, Canada, found that the risk of hospitalization with encephalopathy was significantly higher in patients taking baclofen compared to non-users.
Some key points to consider when selecting an oral muscle relaxant for patients with ESRD undergoing dialysis include:
- The risk of encephalopathy associated with baclofen use in this population 1
- The need for dose reduction in dialysis patients due to decreased renal clearance
- The potential for partial removal of baclofen by hemodialysis, which may require supplemental doses post-dialysis
- The importance of close monitoring for side effects such as sedation, dizziness, and hypotension, especially when initiating therapy
Alternative muscle relaxants such as tizanidine may be considered for patients with ESRD undergoing dialysis, as they have a different mechanism of action and may be safer in this population. Tizanidine is a central alpha-2 adrenergic agonist that can be started at a dose of 2 mg three times daily and increased to 8 mg three times daily as needed. However, it is essential to carefully evaluate the risks and benefits of any medication in this population and to closely monitor patients for potential side effects.
In terms of specific guidance, the study published in 2020 recommends avoiding baclofen in older adults receiving dialysis and considering alternative muscle relaxants instead 1. This recommendation is based on the high risk of encephalopathy associated with baclofen use in this population, and the need for careful monitoring and dose adjustment to minimize the risk of adverse effects.
Overall, the selection of an oral muscle relaxant for patients with ESRD undergoing dialysis requires careful consideration of the potential risks and benefits, as well as close monitoring for potential side effects. Alternative muscle relaxants such as tizanidine should be considered instead of baclofen due to the high risk of encephalopathy associated with its use in this population.