SpringerLink
Log in

QT-Interval Prolongation Associated with Supratherapeutic Guanfacine Concentration: A Case Report

  • Case Report
  • Published:
Journal of Medical Toxicology Aims and scope Submit manuscript

Abstract

Introduction

Guanfacine, an alpha-2 adrenergic agonist, is used to treat attention deficit hyperactivity disorder (ADHD). Although cardiovascular effects including hypotension and bradycardia are common adverse effects of guanfacine, the effect of guanfacine on QT intervals remains unclear. The association between the serum concentration of guanfacine and its toxicity has also not been fully investigated.

Case Report

This is a case of a 21-year-old woman with ADHD who developed repeated presyncope 1 day before admission. She was taking 3 mg of extended-release guanfacine and 50 mg of sertraline. On admission, she had bradycardia and hypotension. An electrocardiogram (ECG) showed a QT interval of 0.68 s and a QTcF interval of 0.648 s. The QT intervals were manually measured and corrected by the Fridericia formula (QTcF = QT/RR1/3). Although she denied taking an overdose of guanfacine and other drugs, we suspected guanfacine toxicity. The serum guanfacine concentration was 13.0 ng/mL on admission and decreased to 3.2 ng/mL on day 1 and 0.4 ng/mL on day 2. Changes in QTcF intervals and her vital signs correlated with serum guanfacine concentrations.

Conclusion

Supratherapeutic serum guanfacine concentrations may induce QT prolongation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price includes VAT (France)

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2

Similar content being viewed by others

Data Availability

This is a case report, all data are in the manuscript.

References

  1. Winograd EJ, Sollee D, Schauben JL, Kunisaki T, Smotherman C, Gautam S. Pediatric guanfacine exposures reported to the National Poison Data System, 2000–2016. Clin Toxicol. 2020;58:49–55.

    Article  CAS  Google Scholar 

  2. Bridwell RE, Larson NP, Rosenthal JB, Wray J, Baker Z, Cibrario A, et al. Guanfacine toxic ingestion with subsequent cardiogenic pulmonary edema. Am J Emerg Med. 2021;39:256.e5-256.e8.

    Article  PubMed  Google Scholar 

  3. Martinez-Raga J, Knecht C, Szerman N, Martinez MI. Risk of serious cardiovascular problems with medications for attention-deficit hyperactivity disorder. CNS Drugs. 2013;27:15–30.

    Article  CAS  PubMed  Google Scholar 

  4. Martin P, Satin L, Kahn RS, Robinson A, Corcoran M, Purkayastha J, et al. A thorough QT study of guanfacine. Int J Clin Pharmacol Ther. 2014;53:301–16.

    Google Scholar 

  5. Schulz M, Schmoldt A, Andresen-Streichert H, Iwersen-Bergmann S. Revisited: therapeutic and toxic blood concentrations of more than 1100 drugs and other xenobiotics. Crit Care. 2020;24:195.

    Article  PubMed  PubMed Central  Google Scholar 

  6. Tsuda Y, Matsuo Y, Matsumoto S, Wajima T. Population pharmacokinetic and exposure-response analyses of guanfacine in Japanese pediatric ADHD patients. Drug Metab Pharmacokinet. 2019;34:365–71.

    Article  CAS  PubMed  Google Scholar 

  7. Fein DM, Hafeez ZF, Cavagnaro C. An overdose of extended-release guanfacine. Pediatr Emerg Care. 2013;29:929–31.

    Article  PubMed  Google Scholar 

  8. Spiller HA, Hays HL, Aleguas A. Overdose of drugs for attention-deficit hyperactivity disorder: clinical presentation, mechanisms of toxicity, and management. CNS Drugs. 2013;27:531–43.

    Article  CAS  PubMed  Google Scholar 

  9. Minns AB, Clark RF, Schneir A. Guanfacine overdose resulting in initial hypertension and subsequent delayed, persistent orthostatic hypotension. Clin Toxicol. 2010;48:146–8.

    Article  CAS  Google Scholar 

  10. Calculator.net. https://www.calculator.net/half-life-calculator.html. Accessed 18 Sept 2023.

  11. Zhang L, Timothy KW, Vincent GM, Lehmann MH, Fox J, Giuli LC, et al. Spectrum of ST-T-wave patterns and repolarization parameters in congenital long-QT syndrome: ECG findings identify genotypes. Circulation. 2000;102:2849–55.

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

We are grateful to our department of clinical laboratory for preserving the serum samples until examination of the drug concentrations.

Funding

None.

Author information

Authors and Affiliations

  1. Department of Emergency Medicine, Hiroshima City Hiroshima Citizens Hospital, 7-33 Motomachi, Naka-Ku, Hiroshima City, 730-8518, Japan

    Fumiya Inoue, Yuji Okazaki, Kenichiro Kashiwa & Toshihisa Ichiba

  2. Department of Forensic Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-Ku, Hiroshima City, 734-8553, Japan

    Akira Namera

Authors
  1. Fumiya Inoue
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Yuji Okazaki
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Kenichiro Kashiwa
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Toshihisa Ichiba
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Akira Namera
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Yuji Okazaki.

Ethics declarations

Ethical Approval

Consent for publication of this case was obtained and provided to the journal in accordance with JMT policy.

Conflicts of Interest

None.

Additional information

Supervising Editor: Andis Graudins, MB BS, PhD

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Inoue, F., Okazaki, Y., Kashiwa, K. et al. QT-Interval Prolongation Associated with Supratherapeutic Guanfacine Concentration: A Case Report. J. Med. Toxicol. 20, 218–221 (2024). https://doi.org/10.1007/s13181-023-00986-8

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s13181-023-00986-8

Keywords

Search

Navigation