Can Atarax (hydroxyzine) cause tachycardia?

Can Atarax (Hydroxyzine) Cause Tachycardia?

Yes, hydroxyzine (Atarax) can cause tachycardia as a side effect, though it is relatively uncommon. Documented cases include supraventricular tachycardia in pediatric patients and cardiac rhythm disturbances in adults, particularly those with pre-existing cardiac conditions.

Cardiovascular Effects of Hydroxyzine

Documented Cardiac Effects

• Hydroxyzine has been associated with tremors, irritability, hyperactivity, jitteriness, increased respiratory and heart rates in case reports 1
• A case report documented supraventricular tachycardia (SVT) in a nine-year-old girl taking clinical doses of hydroxyzine for pruritus, with a heart rate of 250/minute 2
• The patient in the case report had three episodes of palpitations with chest tightness during five months of hydroxyzine treatment, which resolved after discontinuation 2

Mechanism of Action and Cardiac Risk

• Hydroxyzine may produce abnormal ventricular repolarization when given in substantial doses or to susceptible individuals 3
• The medication can potentially prolong the QT interval, which has been documented to cause torsade de pointes in vulnerable patients 4
• Risk may be increased when hydroxyzine is combined with other medications that affect cardiac function, such as phenothiazines, tricyclic antidepressants, antiparkinson drugs, atropine, quinidine, or procainamide 3

Risk Factors for Hydroxyzine-Induced Tachycardia

Patient-Specific Risk Factors

• Pre-existing cardiac conditions increase risk, particularly bradycardia or heart block 4
• An 82-year-old woman with complete atrioventricular block developed torsade de pointes after receiving just 12.5 mg of hydroxyzine for sedation 4
• The elderly may be more susceptible to cardiac effects due to age-related changes in drug metabolism and clearance 4

Dose-Related Considerations

• Higher doses may increase the risk of cardiac effects, though adverse events have been reported even with standard therapeutic doses 2, 3
• In patients with cardiovascular disorders, hydroxyzine has been used at daily doses of 50 mg with reported good tolerability in some studies 5

Clinical Implications and Management

Monitoring Recommendations

• Patients with known cardiac conditions should be monitored more closely when taking hydroxyzine 4, 3
• Particular caution is warranted in patients with:
  • Bradycardia
  • Heart block
  • QT prolongation
  • Electrolyte abnormalities 4

Alternative Medications

• For patients with cardiac risk factors requiring antihistamine therapy, consider newer generation antihistamines with fewer cardiac effects 1
• Non-sedating H1 antihistamines may be preferable alternatives for patients with cardiac concerns 1

Response to Tachycardia

• If tachycardia occurs, discontinuation of hydroxyzine should be considered 2
• In the reported case of SVT, symptoms resolved after hydroxyzine was discontinued 2

Conclusion

While hydroxyzine is generally considered safe in most patients, clinicians should be aware of its potential to cause tachycardia and other cardiac effects, especially in vulnerable populations. Careful monitoring and consideration of alternative medications may be warranted in patients with pre-existing cardiac conditions.