How does acidemia increase the risk for death from cocaine toxicity?

Updated: Sep 01, 2018
  • Author: Lynn Barkley Burnett, MD, EdD, LLB(c); Chief Editor: Sage W Wiener, MD  more...
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Answer

Acidemia is seen in clinically significant toxicity and may play an important role in cocaine-related death. In experimental studies, calcium delivery to myofilaments is decreased and contractile proteins become less responsive in the presence of lowered intracellular pH, resulting in depression of myocardial contractility.

Acidosis also potentiates dysrhythmias by repolarization and depolarization abnormalities that lead to reexcitation states. As pH decreases, calcium is spontaneously released from the sarcoplasmic reticulum, resulting in a transient depolarizing current that can precipitate dysrhythmias during diastole. In addition, acidosis decreases conductance between the gap junctions of cardiac cells, which slows propagation of the action potential. In the presence of cocaine, which diminishes sodium conductance, a severe reduction in conduction velocity may occur, increasing the likelihood of dysrhythmia production by means of reentry excitation.


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