Case of the Month #35 Calcium Channel Blocker Overdose

Published 19/01/2023

What Investigations would you perform?

  • ECG 

    • Phenylalkylamines and benzothiazepines toxicity may result in sinus bradycardias, varying degrees of atrioventricular block, bundle branch block, junctional rhythms and prolonged QT.  

    • Dihydropyridines toxicity can result in a reflex sinus tachycardia.  


  • Blood glucose 

    • Hyperglycaemia is a marker of severity of toxicity 


  • Arterial blood gas  

    • May show a metabolic acidosis and hyperlactatemia 


  • U&Es 

    • Creatinine may be raised due to impaired end organ perfusion 


  • Chest X – ray  

    • May show pulmonary oedema 

  • Echocardiography  

    • Evidence of impaired contractility