Haemodialysis clearance of baclofen.
BACKGROUND
Baclofen is a centrally acting gamma-aminobutyric acid agonist used for spasticity of spinal origin and mainly excreted unchanged by the kidneys. We report haemodialysis clearance and the haemodialysis removal rate constant of baclofen in a comatose patient with baclofen overdose due to acute renal failure.


METHODS
A 60-year-old man with spastic tetraplegia on chronic baclofen therapy was admitted due to pneumonia and acute renal failure. The patient became comatose and, as a result of the baclofen dosage being left unchanged despite a deterioration leading to renal failure due to hypotension, the concentration of baclofen was determined to be in the toxic range (0.70 mg/L). During a 4-hour-long bicarbonate haemodialysis the patient woke up and became completely orientated and cooperative. Baclofen therapy was subsequently stopped, and the patient remained conscious. The pharmacokinetics calculations revealed a baclofen haemodialysis removal rate constant of 0.152 h(-1) and a haemodialysis clearance of 2.14 mL/s.


CONCLUSIONS
Patients on a stable baclofen regime can develop baclofen toxicity due to acute renal failure. Haemodialysis removes baclofen as effectively as normal kidneys, and it would appear that haemodialysis is a reasonable treatment modality in patients with accidental baclofen overdose due to acute renal failure.
Brvar
Miran
M
Poison Control Centre, University Medical Centre Ljubljana, Zaloska cesta 7, 1000 Ljubljana, Slovenia. miran.brvar@kclj.si
Vrtovec
Matjaz
M
Kovac
Damjan
D
Kozelj
Gordana
G
Pezdir
Tomaz
T
Bunc
Matjaz
M
D058186:Acute Kidney Injury / Q000378:metabolism / Q000628:therapy; D019540:Area Under Curve; D001418:Baclofen / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D003128:Coma / Q000139:chemically induced*; D062787:Drug Overdose; D018755:GABA Agonists / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D006435:Renal Dialysis
D018755:GABA Agonists; D001418:Baclofen