Psychiatric Pharmacy Essentials: QTc Prolonging Medications

The QT interval is defined as the amount of time for the ventricles of the heart to repolarize after activation. This number can vary based on an individual’s heart rate and is often corrected to the QTc interval. A prolonged QTc interval is a risk factor for developing torsades de pointes (TdP). Although TdP is a relatively rare event, it is a potentially life-threatening polymorphic ventricular tachycardia that can have severe consequences. The QTc interval is generally considered prolonged when greater than 450 msec for males or greater than 470 msec for females. QTc interval prolongation can be congenital or acquired, with medication-induced QTc prolongation being a concern. Several psychotropic medications are known to prolong the QTc interval. As psychiatric pharmacists, it is imperative that we are familiar with identifying medications that have been associated with QTc prolongation (particularly psychotropic medications), reducing risk, and managing and monitoring QTc interval prolongation.1-2

  • Where can I find summarized information regarding drug-specific QTc interval prolongation risk?3
  • How do I clinically evaluate the risk of TdP in patients on QTc-prolonging medications and/or who have QTc prolongation?4-7
  • Are there any QTc prolongation medication management guidelines available?8-10
  • What are the differences in QTc prolongation among antidepressants and antipsychotics?11-15

Reviewer 1: Christine Sun, PharmD
Reviewer 2: Austin Smith, PharmD, BCPP
2024-2025 AAPP Resident and New Practitioner Committee

References

  1. Indraratna P, Tardo D, Delves M, et al. Measurement and management of QT interval prolongation for general physicians. J Gen Internal Medicine. 2020;35(3):865-873. [PubMed]
  2. Rautaharju PM, Surawicz B, Gettes LS, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology. J Am Coll Cardiol. 2009;53(11):982-91.[PubMed]
  3. CredibleMeds: [Weblink]
    • Website sponsored by the Arizona Center for Education and Research on Therapeutics (AZCERT). The website provides a searchable database of medications that define varying categories of risk of QT prolongation and information for the public and healthcare professionals. Full access requires registration.
  4. Daniel NM, Walsh K, Leach H, et al. Implementation of a QTc-interval monitoring protocol by pharmacists to decrease cardiac risk in at-risk patients in an acute care inpatient psychiatric facility. Ment Health Clin. 2019;9(2):82-87. [PubMed]
  5. Vandael E, Vandenberk B, Vandenberghe J, et al. Development of a risk score for QTc-prolongation: the RISQ-PATH study. Int J Clin Pharm. 2017;39(2):424-432. [PubMed]
  6. Salvati B, Miola A, Toffanin T, et al. Prevalence and risk factors for QTc prolongation in acute psychiatric hospitalization. Prim Care Companion CNS Disord. 2022; 24(1):21. [PubMed]
  7. Girgis SJ, Maroney ME, Liu MT. Evaluation of the use of electrocardiogram monitoring in patients on psychotropic medications that have a risk of QT prolongation. Ment Health Clin. 2016;6(4):171-7. [PubMed]
  8. Drew BJ, Ackerman MJ, Funk M, et al. Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation. Circulation. 2010;121:1047-1060. [PubMed]
  9. Funk MC, Beach SR, Bostwick JR et al. APA resource document on QTc prolongation and psychotropic medications. Am J Psychiatry. 2020;177(3):273-274. [PubMed]
  10. Xiong GL, Pinkhasov A, Mangal JP, et al. QTc monitoring in adults with medical and psychiatric comorbidities: Expert consensus from the association for medicine and psychiatry. J Psychosom Res. 2020;135:110138. [PubMed]
  11. McClelland J, Mathys M. Evaluation of QTc prolongation and dosage effect with citalopram. Ment Health Clin. 2016;6(4):165-70. [PubMed]
  12. Beach SR, Celano CM, Sugrue AM, Adams C, Ackerman MJ, Noseworthy PA, et al. QT Prolongation, Torsades de Pointes, and Psychotropic Medications: A 5-Year Update. Psychosomatics. 2018;59(2):105-122. DOI: 10.1016/j.psym.2017.10.009. PubMed PMID: 29275963.
  13. Funk KA, Bostwick JR. A comparison of the risk of QT prolongation among SSRIs. Ann Pharmacother. 2013;47(10):1330-41. DOI: 10.1177/1060028013501994. PubMed PMID: 24259697.
  14. Jasiak NM, Bostwick JR. Risk of QT/QTc prolongation among newer non-SSRI antidepressants. Ann Pharmacother. 2014;48(12):1620-8. DOI: 10.1177/1060028014550645. PubMed PMID: 25204465.
  15. Harrigan EP, Miceli JJ, Anziano R, et al. A randomized evaluation of the effects of six antipsychotic agents on QTc, in the absence and presence of metabolic inhibition. J Clin Psychopharmacol. 2004;24(1):62-9. [PubMed]