Too much of a good thing: Bicarbonate toxicity following treatment of sodium channel blocker overdose.

Although sodium bicarbonate can be a life-saving antidote for patients with overdoses resulting in sodium channel blockade, there has been a concerning rise in cases referred to the Poisons Information Centre where inappropriately large doses of bicarbonate have been used resulting in iatrogenic harm. We present a series of three clinical cases where excessive bicarbonate was used to treat poisonings and discuss our approach to managing cardiotoxicity secondary to sodium channel blockade. Serial blood gas analysis should be performed when using bicarbonate to ensure pH targets are met and severe alkalaemia, hypernatraemia and hypokalaemia are avoided. We encourage clinicians to contact the Poisons Information Centre (13 11 26) or their local clinical toxicologist when managing patients with life-threatening sodium channel blockade.