From the Guidelines
Patients with impaired renal function undergoing dialysis should take a benzylisoquinoline muscle relaxant, such as atracurium or cisatracurium, as these agents have similar pharmacokinetic and pharmacodynamic profiles in patients with and without renal and hepatic failure 1. The use of these muscle relaxants is recommended due to their unique elimination pathways, which are not heavily reliant on renal function. Atracurium, for example, is eliminated through a combination of organ-independent reactions and metabolism or excretion, making it a suitable option for patients with impaired renal function 1. Cisatracurium, on the other hand, has an overwhelmingly non-enzymatic elimination pathway, which reduces the risk of accumulation and adverse effects in patients with renal failure 1. Some key points to consider when using these muscle relaxants in patients with impaired renal function include:
- Atracurium and cisatracurium have similar pharmacokinetic and pharmacodynamic profiles in patients with and without renal and hepatic failure 1
- The active metabolite of atracurium, laudanosine, accumulates in patients with renal failure but does not reach concentrations causing adverse effects, even after infusion for up to 72 hours 1
- Cisatracurium is more potent than atracurium, resulting in lower doses and reduced amounts of laudanosine generated 1
- Other muscle relaxants, such as rocuronium, may not be suitable for patients with impaired renal function due to their reliance on renal elimination and potential for accumulation and adverse effects 1
From the FDA Drug Label
Tizanidine clearance is reduced by more than 50% in elderly patients with renal insufficiency (creatinine clearance < 25 mL/min) compared to healthy elderly subjects; this would be expected to lead to a longer duration of clinical effect. Tizanidine should be used with caution in renally impaired patients
The patient with impaired renal function undergoing dialysis can take tizanidine with caution, as it is expected to have a longer duration of clinical effect due to reduced clearance in renally impaired patients 2.
- Key considerations:
- Reduced clearance
- Longer duration of clinical effect
- Use with caution in renally impaired patients
From the Research
Muscle Relaxant Options for Patients with Impaired Renal Function
- Patients with impaired renal function undergoing dialysis should avoid certain muscle relaxants due to the risk of toxicity 3.
- Baclofen, a commonly prescribed muscle relaxant, is not recommended for patients with severely reduced kidney function or those on renal replacement therapy due to the risk of neurotoxicity and hemodynamic instability 3.
- For patients undergoing renal transplantation under general anesthesia, vecuronium, atracurium, mivacurium, and rocuronium can be safely used, but the dosage and administration should be carefully monitored 4.
- The onset of some muscle relaxants, such as vecuronium, atracurium, and mivacurium, may be accelerated in patients with end-stage renal failure, while the no-response period of mivacurium may be prolonged 4.
- Repeated incremental doses of vecuronium and rocuronium may prolong the no-response period and duration of action in patients with end-stage renal failure 4.
Alternative Methods for Managing Muscle Cramps
- Application of warm or cold compresses to the extremities during dialysis may help reduce muscle cramps and fatigue, and improve patient comfort 5.
- Exercise therapy during dialysis may also improve muscle strength, quality of life, and reduce the risk of frailty 6.
- However, the use of muscle relaxants, such as those used to manage muscle cramps, may increase the risk of incident frailty in patients with diabetic kidney disease 7.