Last year’s warnings from the FDA about dose-dependent QTc elongation and cardiac arrhythmias including Torsade De Pointes among patients taking citalopram at higher doses have been supplemented by warnings issued by HealthCanada on escitalopram (Lexapro), the S-isomer of racemic citalopram. The FDA’s 2012 guidelines exclude escitalopram but hedge on concluding that the QT effects are limited to the D isomer.
The risk may be heightened in those with pre-existing cardiac problems or patients with abnormal electrolyte levels such as low potassium or magnesium. Of note, this population could include those with bulimia who are actively purging and for whom SSRIs are frequently used. In addition, there may be increased risk among patients who are taking other medications that can potentially cause QTc elongation such as the antipsychotic medication ziprasidone (Geodon).
Current guidelines include the following…
- Among healthy patients with no other medications that could affect cardiac conduction, using no more than 40 mg of citalopram and no more than 20 mg of escitalopram per day
- A “not recommended” classification for use in patients with congenital QT interval prolongation (one step below contraindicated)
- ECG and electrolyte monitoring among higher-risk patients who continue to use the medications
The guidelines don’t give additional information regarding pediatric use, unfortunatley. Escitalopram does have an FDA indication to treat depression in adolescents at least 12 years of age.