Adverse drug event of hypokalaemia-induced cardiotoxicity secondary to the use of laxatives: A systematic review of case reports

What is known and objective: The imbalance in serum potassium caused by laxatives can negatively affect the cardiovascular system, leading to life-threatening consequences. Our objective was to evaluate the reported evidence of adverse events related to the cardiac system due to laxative-induced hypokalaemia from case reports.

Methods: A systematic electronic literature search of PubMed, Embase, the Cochrane Library and Science Direct was conducted for the period 1995-2019. In these databases, search terms describing hypokalaemia and cardiotoxicity were combined with the term laxative use.

Results and discussion: Over the 23 years, 27 incidents were identified in 12 countries. There were 19 female and eight male patients, with ages ranging from 1 month to 93 years. The frequency of reported cases according to severity was the following: severe hypokalaemia 48%, moderate hypokalaemia 44.4% and mild hypokalaemia 7.4%. In 70% of patients, the effect of laxative on the heart was typical hypokalaemic electrographic changes, 7.4% showed abnormal changes in cardiac rhythm, whereas in 18.5%, the cardiotoxicity observed was a very serious kind. Two patients died due to severe cardiac effects.

What is new and conclusion: The laxatives-along with the involvement of some other contributing factors-caused mild-to-severe hypokalaemic cardiotoxicity. These factors were non-adherence of the patient to the recommended dosage, laxative abuse, drug-drug and drug-disease interactions, non-potassium electrolyte imbalances and the use of herbal laxatives. We recommend that laxatives and aggravating factors should be taken into account in the assessment of patients with suspected hypokalaemic cardiotoxicity.

Keywords: adverse drug event; cardiotoxicity; hypokalaemia; laxative.