From the Guidelines
Escitalopram is known to prolong the QT interval more than Zosyn (piperacillin/tazobactam). According to the European Heart Journal study 1, escitalopram, a selective serotonin re-uptake inhibitor (SSRI), has a documented risk of QT interval prolongation, particularly at higher doses. The FDA and EMA have limited the recommended maximum doses of escitalopram due to this risk, especially in patients older than 60 years of age. Some key points to consider include:
- Escitalopram's QT prolonging effect is dose-dependent, with higher doses (>20mg daily) carrying a greater risk
- Patients with pre-existing cardiac conditions, electrolyte abnormalities, or those taking other QT-prolonging medications are at increased risk
- Zosyn, an antibiotic combination, has minimal effects on cardiac repolarization and is not significantly associated with QT prolongation in clinical practice
- The mechanism behind escitalopram's QT prolongation involves interference with potassium channels responsible for cardiac repolarization. In clinical practice, caution should be exercised with escitalopram, and ECG monitoring may be warranted, especially when initiating therapy or increasing doses, particularly in patients with risk factors for QT prolongation, such as congenital long QT syndrome, heart failure, or electrolyte disturbances 1.
From the Research
QT Interval Prolongation Comparison
- There are no direct studies comparing the QT interval prolongation effects of Zosyn (piperacillin/tazobactam) and escitalopram.
- However, several studies have investigated the QT interval prolongation effects of escitalopram:
- A case report found that low-dose escitalopram (5 mg/day) for 2 days was associated with corrected QT interval prolongation in a middle-aged woman 2.
- A study of 713 patients prescribed escitalopram found that patients with QTc prolongation (∆QTc ≥ 30 ms) received higher escitalopram doses (10.3 mg) than those without QTc prolongation (9.4 mg) 3.
- Another study found that escitalopram overdose can lead to QTc interval prolongation, with a reported case of a 33-year-old woman who ingested 15-20 pills of escitalopram (20 mg each) and developed a QTc interval of 491 ms 4.
- In contrast, there is limited information available on the QT interval prolongation effects of Zosyn (piperacillin/tazobactam).
- A comparative study of QT prolongation with serotonin reuptake inhibitors found that only citalopram and escitalopram had a significant association with QT prolongation, suggesting that QT prolongation is not a class effect of serotonin reuptake inhibitors 5.
- A study on the impact of hospital pharmacist interventions on the combination of citalopram or escitalopram with other QT-prolonging drugs found that a high number of hospital prescriptions including citalopram or escitalopram with another QT-prolonging drug occurred, highlighting the importance of involvement of clinical pharmacists in prevention of potential adverse drug reactions 6.