Emergency management of calcium channel blocker overdose

Abstract

Calcium channel blockers (CCBs) are commonly used in South Africa (SA) in the management of hypertension and other cardiovascular disease. Their ubiquitous availability makes them a common agent in drug overdose (OD), whether through accidental ingestion or deliberate self-harm. It is essential that medical practitioners know how to recognise and manage CCB OD, as severe CCB OD is often fatal. As there is a lack of local literature in SA, we highlight the general principles of management of CCB OD, as well as complications and problems that may be encountered during treatment. This narrative review is based on existing clinical guidelines, retrospective studies and systematic reviews on the emergency management of CCB OD. High-dose insulin euglycaemic therapy has become the mainstay of treatment in severe CCB OD. The rationale, the recommended protocol for its use and its adverse effects are described.S Afr Med J 2019;109(9):635-638. https://doi.

Amlodipine poisoning management

“…The hallmark of CCB overdose is circulatory shock due to bradycardia, poor cardiac contractility and profound peripheral vasodilation, which leads to tissue hypoperfusion and target organ damage. 1 CCBs of all subclasses reduce pancreatic insulin secretion and induce end-organ insulin resistance causing hyperglycaemia. Metabolic side-effects include hyperglycaemia, hypoinsulinaemia and impairment of the cardiac myocyte adaptive response.…”

“…They are therefore used in the management of hypertension and angina pectoris. 1 The non-dihydropyridines have more significant myocardial effects thereby decreasing conduction and heart rate. They are therefore preferentially used in supraventricular arrhythmias and angina including Prinzmetal's angina.…”

“…4,5 Calcium channels are functionally important not only in cardiac myocytes and vascular smooth muscle cells but also in islet beta cells of the pancreas, the central nervous system and skeletal muscle. 1 Therefore blockade of calcium channels in the pancreatic beta cells can cause reduced insulin release. 1,4 Ingestion of excessive CCBs, either accidental or in deliberate self-harm, is one of the most potentially lethal drug overdoses.…”

“…1 Therefore blockade of calcium channels in the pancreatic beta cells can cause reduced insulin release. 1,4 Ingestion of excessive CCBs, either accidental or in deliberate self-harm, is one of the most potentially lethal drug overdoses. 1 The exact toxic dose has not been fully established, however it is recommended that adult patients be monitored for toxicity if more than 10 mg amlodipine was ingested (> 0.3 mg/kg in children).…”

“…1,4 Ingestion of excessive CCBs, either accidental or in deliberate self-harm, is one of the most potentially lethal drug overdoses. 1 The exact toxic dose has not been fully established, however it is recommended that adult patients be monitored for toxicity if more than 10 mg amlodipine was ingested (> 0.3 mg/kg in children). 1 Verapamil and diltiazem are the most lethal CCBs in overdose and the patient should be monitored if more than 120 mg verapamil immediate-release or more than 480 mg verapamil sustained-release (> 2.5 mg/kg in children) was ingested.…”