Retrospective analysis of intravenous calcium in digitoxicity

Retrospective analysis of intravenous calcium in digitoxicity

Conventional wisdom says that intravenous calcium should be avoided in digitoxicity. A retrospective analysis assessed this aspect. Digoxin being a sodium-potassium ATPase inhibitor, digoxin overdose can be associated with hyperkalemia, which would prompt calcium administration in any other situation. Michael Levine, Heikki Nikkanen and Daniel J Pallin [1] could retrieve records of about one hundred and sixty patients who had been diagnosed with digitoxicity over seventeen and a half years in a large teaching hospital. It was found that twenty three of these patients had received calcium. It was interesting to note that no life threatening arrhythmias were documented within one hour of calcium administration. Mortality was similar between those who received or not received calcium administration. In fact on multivariate analysis, calcium administration was associated with a decreased odds of death, though not statistically significant. Every milli equivalent per liter rise in serum potassium was associated with a higher odds ratio of 1.5 for mortality. Thus the investigators found no support for the conventional wisdom that intravenous calcium is contraindicated in digitoxicity. Of course we cannot discard conventional wisdom based on this small retrospective study. We need more information on this aspect.

Reference

1. Michael Levine, Heikki Nikkanen, Daniel J Pallin. The Effects of Intravenous Calcium in Patients With Digoxin Toxicity. J Emerg Med. 2011 Jan;40(1):41-6.