Does Atarax (hydroxyzine) cause prolonged QTc interval?

From the Guidelines

Atarax (hydroxyzine) is a medication that can potentially cause QTc prolongation, as listed in the table of QT-interval-prolonging medications in pediatrics 1. This effect is generally mild at standard doses, but the risk increases with higher doses, in patients with pre-existing cardiac conditions, electrolyte abnormalities (especially low potassium or magnesium), or when combined with other QT-prolonging medications. Some key points to consider include:

• Typical therapeutic doses of hydroxyzine (25-100 mg) pose minimal risk in healthy individuals, but caution is warranted in vulnerable populations.
• The mechanism involves hydroxyzine's ability to block potassium channels in cardiac cells, which can delay ventricular repolarization and extend the QT interval.
• Patients with heart disease, the elderly, and those taking multiple medications should be monitored more closely.
• If you're concerned about QTc prolongation risk, consider ECG monitoring before and during treatment, maintaining normal electrolyte levels, and discussing alternative medications with lower QT-prolonging potential with your healthcare provider. It's essential to weigh the benefits and risks of using Atarax, especially in patients with pre-existing cardiac conditions or those taking other QT-prolonging medications, as the potential for QTc prolongation can increase the risk of dysrhythmias such as torsades de pointes 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. Hydroxyzine is contraindicated in patients with a prolonged QT interval.

Atarax (hydroxyzine) can cause prolonged QTc.

• The drug label directly states that cases of QT prolongation have been reported during post-marketing use of hydroxyzine 2.
• Additionally, hydroxyzine is contraindicated in patients with a prolonged QT interval, indicating a known risk of QT prolongation 2.

From the Research

Atarax and Prolonged QTc Interval

• Atarax, also known as hydroxyzine, 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 3, 4.
• A case study reported a patient with a HERG mutation who experienced syncope after taking hydroxyzine, with a QTc interval of 630 ms that shortened to 464 ms after cessation of the drug 4.
• 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 for QT prolongation and TdP compared to those without risk factors 5.

Risk Factors for QT Prolongation

• Underlying medical conditions, such as cardiovascular disorders, can increase the risk of QT prolongation and TdP associated with hydroxyzine use 3.
• Concomitant medications that can induce arrhythmia can also increase the risk of QT prolongation and TdP 3.
• Genetic mutations, such as the A614V-HERG mutation, can also increase the risk of QT prolongation and TdP associated with hydroxyzine use 4.