How often should patients on Selective Serotonin Reuptake Inhibitors (SSRI) and hydroxyzine have an electrocardiogram (EKG)?

EKG Monitoring for Patients on SSRIs and Hydroxyzine

Patients on SSRIs and hydroxyzine should have a baseline EKG before starting treatment and follow-up EKGs when dosages change or new risk factors develop, but do not require routine periodic EKGs if the baseline is normal and no new risk factors emerge.

Risk Assessment for QT Prolongation

Both SSRIs and hydroxyzine have been associated with QT interval prolongation, which can increase the risk of dangerous arrhythmias:

• Hydroxyzine has been identified as having a "conditional risk of Torsade de Pointes (TdP)" 1 and can produce abnormal ventricular repolarization, particularly at higher doses or in susceptible individuals 2.

• SSRIs like escitalopram, fluoxetine, and citalopram have been associated with QT prolongation 3. For escitalopram specifically, FDA labeling indicates that none of the patients in clinical trials had a QTcF interval >500 msec or a prolongation >60 msec compared to 0.2% in the placebo group 4.

Recommended EKG Monitoring Protocol

Initial Assessment:

• Obtain a baseline EKG before starting the combination of SSRI and hydroxyzine
• Assess for pre-existing QT prolongation or other cardiac abnormalities

Follow-up Monitoring:

• No routine periodic EKGs are required if:

  • Baseline EKG is normal
  • Patient remains asymptomatic
  • No changes in medication dosage
  • No new risk factors develop

• Obtain follow-up EKG when:

  • Changing dosage of either medication
  • Adding new medications that may affect QT interval
  • Patient develops symptoms (palpitations, syncope, dizziness)
  • New risk factors emerge (electrolyte abnormalities, heart disease)

Risk Factors Requiring More Vigilant Monitoring

More frequent EKG monitoring is warranted in patients with:

1. Pre-existing cardiac conditions:

   • Ischemic heart disease
   • Heart failure
   • Structural heart disease
   • History of arrhythmias

2. Concomitant QT-prolonging medications 5:

   • Antipsychotics (especially phenothiazines)
   • Tricyclic antidepressants
   • Certain antibiotics (erythromycin, pentamidine)
   • Antiarrhythmic drugs

3. Electrolyte abnormalities:

   • Hypokalemia
   • Hypomagnesemia
   • Hypocalcemia

4. Other risk factors:

   • Advanced age
   • Female gender
   • Renal dysfunction
   • Hepatic dysfunction

Special Considerations

• Combination risk: The risk of QT prolongation is higher when hydroxyzine is combined with other medications known to induce arrhythmia 1.

• Dose-dependent risk: Higher doses of both medications increase the risk of QT prolongation.

• Monitoring in CKD: Patients with chronic kidney disease may be at higher risk, as studies have shown that hydroxyzine is associated with QT prolongation (+4±1 milliseconds) in this population 3.

Common Pitfalls to Avoid

1. Failing to obtain a baseline EKG before starting treatment

2. Not reassessing EKG when adding new QT-prolonging medications to the regimen

3. Overlooking electrolyte abnormalities that can exacerbate QT prolongation

4. Ignoring patient symptoms that might indicate arrhythmias (palpitations, dizziness, syncope)

5. Continuing medications without reassessment when risk factors change

The American College of Cardiology/American Heart Association guidelines emphasize that the frequency of repeat ECGs should be determined by the specific condition and left to the judgment of the patient's physician 5, but they do recommend ECGs after initiation of drug therapy, after changes in therapy, and after addition of other drugs that may interact and have cardiac effects.