Recommendations from the EXTRIP workgroup on extracorporeal treatment for baclofen poisoning

Baclofen toxicity results from intentional self-poisoning ("acute baclofen poisoning") or accumulation of therapeutic dose in the setting of impaired kidney function. Standard care includes baclofen discontinuation, respiratory support and seizure treatment. Use of extracorporeal treatments (ECTRs) is controversial. To clarify this, a comprehensive review of the literature on the effect of ECTRs in baclofen toxicity was performed and recommendations following EXTRIP methods were formulated based on 43 studies. (1 comparative cohort, 1 aggregate results cohort, 1 pharmacokinetic modeling, and 40 patient reports or series). Toxicokinetic data were available for 20 patients. Baclofen's dialyzability is limited by a high endogenous clearance and a short half-life in patients with normal kidney function. The workgroup assessed baclofen as "Moderately dialyzable" by intermittent hemodialysis for patients with normal kidney function (quality of evidence C) and "Dialyzable" for patients with impaired kidney function (quality of evidence C). Clinical data were available for 25 patients with acute baclofen poisoning and 46 patients with toxicity from therapeutic baclofen in kidney impairment. No deaths or sequelae were reported. Mortality in historical controls was rare. No benefit of ECTR was identified in patients with acute baclofen poisoning. Indirect evidence suggests a benefit of ECTR in reducing the duration of toxic encephalopathy from therapeutic baclofen in kidney impairment. These potential benefits were balanced against added costs and harms related to the insertion of a catheter, the procedure itself, and the potential of baclofen withdrawal. Thus, the EXTRIP workgroup suggests against performing ECTR in addition to standard care for acute baclofen poisoning and suggests performing ECTR in toxicity from therapeutic baclofen in kidney impairment, especially in the presence of coma requiring mechanical ventilation.

Muscle Relaxant Use Among Hemodialysis Patients: Prevalence, Clinical Indications, and Adverse Outcomes

RATIONALE & OBJECTIVE

Muscle relaxants are often used to treat musculoskeletal pain or cramping, which are commonly experienced by hemodialysis patients. However, the extent to which muscle relaxants are prescribed in this population and the risks associated with their use have not been characterized.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

140,899 Medicare-covered adults receiving hemodialysis in 2011, identified in the US Renal Data System.

EXPOSURE

Time-varying muscle relaxant exposure.

OUTCOMES

Primary outcomes were time to first emergency department visit or hospitalization for altered mental status, fall, or fracture. Secondary outcomes were death and composites of death with each of the primary outcomes.

ANALYTICAL APPROACH

Multivariable Cox regression analysis.

RESULTS

10% of patients received muscle relaxants in 2011. 11%, 6%, 3%, and 13% had an episode of altered mental status, fall, fracture, and death, respectively. Muscle relaxant use was associated with higher risk for altered mental status (HR, 1.39; 95% CI, 1.29-1.51) and fall (HR, 1.18; 95% CI, 1.05-1.33) compared to no use. Muscle relaxant use was not statistically significantly associated with higher risk for fracture (HR, 1.17; 95% CI, 0.98-1.39). Muscle relaxant use was associated with lower hazard of death (HR, 0.85; 95% CI, 0.76-0.94). However, hazards were higher for altered mental status or death (HR, 1.17; 95% CI, 1.10-1.25), fall or death (HR, 1.14; 95% CI, 1.06-1.22), and fracture or death (HR, 1.10; 95% CI, 1.01-1.20).

LIMITATIONS

A causal association between muscle relaxant use and outcomes cannot be inferred, and residual confounding cannot be excluded. Exposure and outcomes were ascertained using administrative claims.

CONCLUSIONS

Muscle relaxant use was common in hemodialysis patients and associated with altered mental status and falls. We could not rule out a clinically meaningful association between muscle relaxant use and fracture. The lower risk for death with muscle relaxants may have been the result of residual confounding. Future research to define the appropriate use of muscle relaxants in this population is warranted.

A nationwide register-based survey of baclofen toxicity

To study the use and misuse (poisonings) of baclofen in the time period of 2007-2012 and to evaluate the severity and clinical symptoms of poisonings including ingested baclofen. The National Patient Register (NPR) was searched for admissions due to baclofen poisonings from 2007 to 2012. The search was conducted with ICD-10 codes for poisoning, self-harm and suicide, and coupled with the baclofen ATC code. All enquiries about baclofen to the Danish Poison Information Centre (DPIC) in the same period were evaluated. Demographic and clinical data were extracted, and the poisonings were classified according to the Poison Severity Score. The number of baclofen poisonings did not increase from 2007 to 2012. Thirty-eight admissions with baclofen poisoning were registered at the NPR; however, only one-third of the reviewed DPIC cases were registered at the NPR with the correct coding. In the group of severely poisoned patients (PSS 3), three patients had only ingested baclofen (mean 2000 mg; SD 500 mg) and eight patients had ingested baclofen together with alcohol or psychotropic drugs (mean 900 mg; SD 641 mg). All patients presented with deep coma and respiratory depression. Additionally, seizures and cardiovascular events (mild hypo- or hypertension and bradycardia) occurred. There is a substantial degree of underreporting of baclofen poisonings in Denmark. Symptoms of baclofen poisoning progress very fast, and toxicity was observed even with doses as low as 150 mg. We therefore recommend that observation and treatment of these patients should be carried out in an intermediate- or intensive care unit. The most important treatment is the maintenance of a protected airway and respiration.