Successful use of sustained low efficiency dialysis in a case of severe phenobarbital poisoning

Abstract

A 30-year-old female presented with coma and subsequent cardiac arrest caused by phenobarbital overdosage, requiring ventilatory and vasopressor support. She had also developed severe hypoxia following gastric aspiration. Initial therapy, including activated charcoal and forced alkaline diuresis, failed to significantly lower her drug levels and there was minimal neurological improvement. As she was hemodynamically unstable, and unsuitable for conventional dialysis, she was put on sustained low efficiency dialysis (SLED) to facilitate drug removal. SLED resulted in marked reduction in plasma level of phenobarbital, which eventually led to early extubation, improved cognition and aided full recovery. Thus, we concluded that SLED can be an effective alternative in cases of severe phenobarbital poisoning, where conventional hemodialysis or hemoperfusion cannot be initiated, to hasten drug elimination and facilitate early recovery.

Successful haemofiltration therapy in severe phenobarbital overdose

“…Toxicity presents as sedation that can ultimately progress to coma, respiratory depression, hypotension, and cardiac arrest or death. 6 With a prolonged half-life of 53-118 hours, secondary to its liver metabolism and renal excretion, serum drug levels take days to decline. 6 For our patient, this resulted in 4 days of prolonged intubation.…”

“…6 With a prolonged half-life of 53-118 hours, secondary to its liver metabolism and renal excretion, serum drug levels take days to decline. 6 For our patient, this resulted in 4 days of prolonged intubation. It was likely further compounded by the additional 40mg clonazepam that was ingested, a central nervous system depressant.…”

“…6 Haemodialysis and haemofiltration is highly effective for phenobarbital due to its high-water solubility, low molecular weight and small volume of distribution. 6 Its plasma clearance by high-flux haemodialysis is 30 times that of hepatic clearance, and 10 times that of activated charcoal clearance. 2,15 Although the estimated V d was high at 347.02L, suggesting that there was a higher concentration in tissues than in plasma, the other factors mentioned above convinced us that extracorporeal treatment was still feasible.…”

“…6 Haemoperfusion is ideal in the removal of lipid soluble or highly protein bound drugs. 6 Haemodialysis and haemofiltration is highly effective for phenobarbital due to its high-water solubility, low molecular weight and small volume of distribution. 6 Its plasma clearance by high-flux haemodialysis is 30 times that of hepatic clearance, and 10 times that of activated charcoal clearance.…”

“…3,4,6,[9][10][11][12][13][14] Haemodialysis involves solute removal by diffusion whereas haemofiltration uses convection with hydrostatic pressure inducing plasma water filtration across the haemofilter. 6 Haemoperfusion is ideal in the removal of lipid soluble or highly protein bound drugs. 6 Haemodialysis and haemofiltration is highly effective for phenobarbital due to its high-water solubility, low molecular weight and small volume of distribution.…”