Genetic factors contribute to medication-induced QT prolongation: A review

Multiple extreme overdose of antipsychotics with minimal side effects: A case report

Key Clinical Message

Antipsychotic drug treatment is a commonly used therapeutic strategy in the field of psychiatry. Rational and standardized use of antipsychotics is crucial in clinical practice, and excessive use of antipsychotics may lead to severe toxic reactions. Thus, attention should be given to the monitoring of drug concentration and examination of organ function.

Abstract

Excessive use of antipsychotics can cause a variety of adverse effects, including dysfunction of the liver and other organs. Liver cytochrome P450 (CYP450) enzymes play an important role in the metabolism of antipsychotics, and metabolizer types of CYP450 enzymes may influence the therapeutic effects. In this case report, we introduced a 52-year-old woman with a 23-year history of schizophrenia who took excessive doses of multiple antipsychotics and other herbal preparations for nearly 2 years, with poor response to treatment and minor side reactions to the antipsychotics. Pharmacogenomic examination showed that this patient was a CYP1A2 ultra-rapid metabolizer. The examination and treatment of this patient may provide a reference for the management of similar cases with poor response to an alarming tolerance for antipsychotics.

Risk Stratification of QTc Prolongation in Critically Ill Patients Receiving Antipsychotics for the Management of Delirium Symptoms

BACKGROUND

Patients experiencing significant agitation or perceptual disturbances related to delirium in an intensive care setting may benefit from short-term treatment with an antipsychotic medication. Some antipsychotic medications may prolong the QTc interval, which increases the risk of potentially fatal ventricular arrhythmias. In this targeted review, we describe the evidence regarding the relationships between antipsychotic medications and QTc prolongation and practical methods for monitoring the QTc interval and mitigating arrhythmia risk.

METHODS

Searches of PubMed and Cochrane Library were performed to identify studies, published before February 2023, investigating the relationships between antipsychotic medications and QTc prolongation or arrhythmias.

RESULTS

Most antipsychotic medications commonly used for the management of delirium symptoms (eg, intravenous haloperidol, olanzapine, quetiapine) cause a moderate degree of QTc prolongation. Among other antipsychotics, those most likely to cause QTc prolongation are iloperidone and ziprasidone, while aripiprazole and lurasidone appear to have minimal risk for QTc prolongation. Genetic vulnerabilities, female sex, older age, pre-existing cardiovascular disease, electrolyte abnormalities, and non-psychiatric medications also increase the risk of QTc prolongation. For individuals at risk of QTc prolongation, it is essential to measure the QTc interval accurately and consistently and consider medication adjustments if needed.

CONCLUSIONS

Antipsychotic medications are one of many risk factors for QTc prolongation. When managing agitation related to delirium, it is imperative to assess an individual patient's risk for QTc prolongation and to choose a medication and monitoring strategy commensurate to the risks. In intensive care settings, we recommend regular ECG monitoring, using a linear regression formula to correct for heart rate. If substantial QTc prolongation (eg, QTc > 500 msec) is present, a change in pharmacologic treatment can be considered, though a particular medication may still be warranted if the risks of discontinuation (eg, extreme agitation, removal of invasive monitoring devices) outweigh the risks of arrhythmias.

AIMS

This review aims to summarize the current literature on relationships between antipsychotic medications and QTc prolongation and to make practical clinical recommendations towards the approach of antipsychotic medication use for the management of delirium-related agitation and perceptual disturbances in intensive care settings.