Background Calcium channel blocker (CCB) toxicity most commonly follows deliberate overdose. However, severe toxicity at therapeutic doses may occur in susceptible individuals. Severe CCB toxicity often presents with clinical features of bradycardia, hypotension, hyperglycaemia, and lactic acidosis.
Aim To highlight the potential for life-threatening cardiogenic shock from verapamil at therapeutic doses in susceptible individuals. Emphasise early recognition of the metabolic characteristics and haemodynamic features of CCBs, including reversibility with prompt, focused treatment.
Clinical details An independent woman, aged in her 80s, with multiple cardiovascular comorbidities developed severe cardiogenic shock following an increase in dose of sustained-release verapamil for rapid atrial fibrillation during admission for presumed infective exacerbation of chronic obstructive pulmonary disease. She presented with hypotension, bradycardia, hypothermia, severe lactic acidosis, hyperkalaemia, and marked hyperglycaemia. Bedside echocardiography demonstrated global ventricular systolic impairment. The patient was managed with fluid resuscitation, ephedrine boluses, adrenaline infusion, treatment of hyperkalaemia, and early critical care retrieval.
Outcome Haemodynamic stability was rapidly restored with normalisation of ventricular function within 24h. The patient made a full recovery.
Conclusion This case highlights life-threatening cardiogenic shock occurring at therapeutic dosing of sustained-release verapamil in a vulnerable patient, and emphasises the importance of early physiological recognition, metabolic pattern awareness, and targeted inotropic support.