Does Celexa (citalopram) and Remeron (mirtazapine) prolong QT interval?

From the Guidelines

Celexa (citalopram) and Remeron (mirtazapine) can both potentially prolong the QT interval, with Celexa having a more significant effect, especially at higher doses, as noted in the study by 1. When considering the use of these medications together, it's essential to be aware of the potential for additive effects on QT prolongation, which can increase the risk of cardiac rhythm disturbances, such as torsades de pointes, ventricular tachycardia, and sudden death, as highlighted in the study by 2. The FDA has limited the maximum recommended dose of Celexa to 40mg daily (20mg for older adults or those with liver impairment) due to the risk of QT prolongation, as mentioned in the study by 1. Some key points to consider when prescribing these medications include:

• Monitoring patients for symptoms like palpitations, dizziness, or fainting, which could indicate cardiac rhythm disturbances, as suggested in the study by 3.
• Regular medical follow-ups and possibly ECG monitoring, especially when starting treatment or changing doses, as recommended in the study by 4.
• Maintaining normal potassium and magnesium balance to reduce the risk of QT prolongation, as emphasized in the study by 4.
• Avoiding the use of QT-prolonging medications in patients with long QT syndrome unless there is no suitable alternative, as stated in the study by 4. It's crucial to weigh the benefits and risks of using these medications together and to consider alternative treatment options, especially for patients with pre-existing heart conditions or electrolyte abnormalities, as noted in the study by 2.

From the FDA Drug Label

Citalopram causes dose-dependent QTc prolongation, an ECG abnormality that has been associated with Torsade de Pointes (TdP), ventricular tachycardia, and sudden death, all of which have been observed in postmarketing reports for citalopram The maximum mean (upper bound of the 95% one-sided confidence interval) difference from placebo were 8.5 (10.8) and 18.5 (21. 0) msec for 20 mg and 60 mg citalopram, respectively. The effect of mirtazapine tablets on QTc interval was assessed in healthy subjects. At a dose of 75 mg (1. 67 times the maximum recommended dosage), mirtazapine tablets do not prolong the QTc interval to a clinically meaningful extent.

Celexa (citalopram):

• Prolongs QT interval: Yes, dose-dependent QTc prolongation
• Risk of Torsade de Pointes: Associated with Torsade de Pointes, ventricular tachycardia, and sudden death

Remeron (mirtazapine):

• Prolongs QT interval: No, does not prolong the QTc interval to a clinically meaningful extent at a dose of 75 mg (1.67 times the maximum recommended dosage)
• Risk of Torsade de Pointes: Not mentioned in the label as a risk associated with mirtazapine use 5

From the Research

QT Interval Prolongation with Celexa (Citalopram) and Remeron (Mirtazapine)

• Celexa (citalopram) has been associated with QT interval prolongation, particularly at higher doses 6, 7, 8.
• Studies have shown that citalopram can cause a significant prolongation of the QTc interval, especially in elderly patients or those with underlying heart conditions 7, 8.
• Remeron (mirtazapine) is not directly mentioned in the provided studies as a cause of QT interval prolongation.
• However, it is essential to note that the risk of QTc prolongation can be increased by various factors, including medications, genetics, gender, cardiovascular status, pathological conditions, and electrolyte disturbances 9, 10.

Comparison of SSRIs and QT Prolongation

• A comparison of SSRIs found that citalopram is more likely to cause QT prolongation than other SSRIs, such as fluoxetine, fluvoxamine, and sertraline 6.
• Paroxetine was found to have the lowest risk of QTc prolongation among the SSRIs studied 6.
• Escitalopram, which is closely related to citalopram, may also cause dose-related QT prolongation 6.

Clinical Recommendations

• Regular ECG monitoring is recommended for patients at risk of QTc prolongation, especially when using medications that may increase this risk 9, 10.
• Clinicians should assess individual patient risk factors for QTc prolongation and choose a medication and monitoring strategy accordingly 10.
• The use of citalopram may need to be avoided or carefully monitored in patients with a high risk of QTc prolongation, such as the elderly or those with underlying heart conditions 7, 8.