Bring QTc prolongation to the forefront of mental health assessment


As pharmaceutical research continues to expand in the field of serious mental illness, it is important to bring awareness to QTc prolongation as an adverse effect of antipsychotic and antidepressant medications. QTc prolongation has been associated with arrhythmias such as torsades de pointes (TdP).

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TdP is a potentially life-threatening ventricular arrhythmia caused by excess sodium influx or reduced potassium influx into the myocardium. This excess of positively charged ions produces a prolonged QT interval, which is measured by the electrocardiogram.

Patients under the care of psychiatric facilities, particularly those taking antipsychotic and antidepressant medications, face an increased risk of prolonged QTc interval. A review in the journal International Clinical Psychopharmacology indicates that certain antipsychotic agents are associated with QTc prolongation, including, but not limited to, haloperidol, olanzapine, quetiapine, risperidone, thioridazine, and ziprasidone. Similarly, antidepressants—particularly selective serotonin reuptake inhibitors, tricyclic antidepressants, and lithium—have demonstrated similar effects on the QT interval.

In addition to assessing a patient’s medical history, it is also important to evaluate demographic risk factors related to QTc prolongation. A 2022 study identified factors such as heart failure, atrial fibrillation, high blood pressure, age 65 and older, and gender (female) as potential demographic risk factors.

To reduce a patient’s risk, medical professionals can work on reducing non-drug risks through healthy lifestyle choices. This will allow health care professionals to work to reduce the risks associated with patients’ prescribed medications. If the patient is young and without other cardiovascular risk factors, promoting a healthy lifestyle is beneficial to prevent future cardiovascular disease. If patients already have cardiovascular disease, they should follow their treatment closely to optimize their ability to manage their conditions.

Pharmacists and physicians need to monitor if the patient’s QT interval prolongs more than 470 ms in women and more than 450 ms in men. When patients have a QT interval of 500 ms or longer, they have an increased risk of developing cardiac arrhythmias such as TdP, as described previously.

To assess a patient’s susceptibility to QT prolongation, the MED Safety Scan (MSS) QT Prolongation Risk Score is a valuable tool. This tool is designed to use the CredibleMeds website’s database to evaluate QTc prolongation warnings, also known as “2U8 drug warnings.”

It provides risk scores based on 2 categories:

  • Medications with a “known risk of TdP” are definitely associated with QTc prolongation and TdP.
  • “Potential risk of TdP” for drugs that have a risk of QTc prolongation, yet evidence associated with TdP is lacking.

MSS can determine the risk of each drug and can also calculate the severity of drug-drug interactions, providing a more comprehensive assessment.

In the context of patients admitted to an inpatient psychiatric facility, researchers say it is important to evaluate the patient’s MSS QT risk score when establishing the patient’s clinical plan. Although each assessment takes approximately 15 to 20 minutes to complete, it should be performed during the initiation of a new medication or whenever dosage adjustment is necessary.

To ensure patient safety, the clinical team should continuously monitor QTc during treatment to avoid the risk of potentially fatal arrhythmias, such as TdP, caused by a prolonged QT interval.

About the Author

Samantha Gorski is a 2025 PharmD candidate at the University of Connecticut.

Reference

Demler TL, O’Donnell C. Navigating the pharmacologic complications of QTc prolongation: assessing the cumulative burden in individuals with severe mental illness. Int Clin Psychopharmacol. 2023 Nov 1;38(6):375-383. doi:10.1097/YIC.0000000000000473. ePUB 2023 May 15. PMID: 37381133.

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