From the Guidelines
Hydroxyzine should be used with caution in patients with cardiac conditions due to its potential to prolong the QT interval, which can increase the risk of dangerous heart rhythm disturbances. Patients with pre-existing cardiac disease, electrolyte abnormalities, or those taking other QT-prolonging medications should avoid hydroxyzine or use it at the lowest effective dose with careful monitoring. The maximum recommended daily dose is 100mg for adults, with lower doses (50mg daily maximum) advised for elderly patients who are more susceptible to cardiac effects. According to a study published in the Journal of the American College of Cardiology 1, hydroxyzine is listed as a medication that can prolong the QT interval, which can increase the risk of torsades de pointes. The QT-prolonging effect occurs because hydroxyzine blocks potassium channels in cardiac cells, delaying repolarization of the heart. This risk is dose-dependent and more pronounced with higher blood levels of the medication. Patients should report any symptoms like palpitations, dizziness, or fainting while taking hydroxyzine. Healthcare providers should consider obtaining baseline and follow-up ECGs in high-risk patients, particularly those with heart failure, bradycardia, or electrolyte disturbances, and should avoid combining hydroxyzine with other medications known to prolong the QT interval, as recommended by the American Heart Association and the American College of Cardiology Foundation 1.
Some key points to consider when prescribing hydroxyzine include:
- Monitoring patients for signs of QT prolongation, such as palpitations, dizziness, or fainting
- Avoiding the use of hydroxyzine in patients with pre-existing cardiac disease, electrolyte abnormalities, or those taking other QT-prolonging medications
- Using the lowest effective dose and avoiding high doses or prolonged use
- Considering alternative medications that do not prolong the QT interval
- Obtaining baseline and follow-up ECGs in high-risk patients to monitor for QT prolongation.
It is essential to weigh the benefits and risks of using hydroxyzine in patients with cardiac conditions and to carefully monitor them for any signs of QT prolongation or other cardiac effects, as recommended by the Pediatrics journal 1.
From the FDA Drug Label
QT Prolongation/Torsade de Pointes (TdP): Cases of QT prolongation and Torsade de Pointes have been reported during post-marketing use of hydroxyzine. The majority of reports occurred in patients with other risk factors for QT prolongation/TdP (pre-existing heart disease, electrolyte imbalances or concomitant arrhythmogenic drug use) Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, a family history of long QT syndrome, other conditions that predispose to QT prolongation and ventricular arrhythmia, as well as recent myocardial infarction, uncompensated heart failure, and bradyarrhythmias Caution is recommended during the concomitant use of drugs known to prolong the QT interval. Hydroxyzine overdose may cause QT prolongation and Torsade de Pointes ECG monitoring is recommended in cases of hydroxyzine overdose.
Hydroxyzine may have cardiac effects, including QT prolongation and Torsade de Pointes, especially in patients with pre-existing heart conditions or when used with other drugs that prolong the QT interval.
- Key considerations:
From the Research
Cardiac Effects of Hydroxyzine
- Hydroxyzine, a first-generation sedating antihistamine, has been linked to cardiac safety concerns, including QT prolongation and torsade de pointes (TdP) 3, 4.
- Studies have shown that hydroxyzine can inhibit human ether-a-go-go-related gene (hERG) potassium ion channels, which can lead to QT prolongation and TdP 3, 4.
- A case study reported a patient with a HERG mutation who experienced syncope after taking hydroxyzine, highlighting the potential risk of cardiac arrhythmias in patients with underlying genetic mutations 4.
Risk Factors for Cardiac Effects
- Patients with underlying medical conditions, such as cardiovascular disorders, or those taking concomitant medications that can induce arrhythmia, are at increased risk of QT prolongation and TdP when taking hydroxyzine 3.
- The combination of cardiovascular disorders and concomitant treatment with drugs known to induce arrhythmia was identified as the greatest combined risk factor for QT prolongation and TdP 3.
Regulatory Advisories and Hydroxyzine Initiation
- Regulatory advisories on hydroxyzine and risk of QT prolongation and TdP were issued in the UK and Canada, leading to a decrease in hydroxyzine initiation in the UK but not in Canada 5.
- The decrease in hydroxyzine initiation in the UK was not significantly different for patients with risk factors compared to those without risk factors 5.