Summary

Citalopram and escitalopram are both selective serotonin reuptake inhibitors (SSRIs) that should not be used together due to increased risk of serotonin syndrome and enhanced side effects. Since escitalopram is the active S-enantiomer of citalopram, concurrent use provides no therapeutic benefit while significantly increasing toxicity risk.

Introduction

Citalopram (Celexa) is a selective serotonin reuptake inhibitor (SSRI) antidepressant used to treat major depressive disorder and various anxiety disorders. Escitalopram (Lexapro) is also an SSRI antidepressant that is actually the S-enantiomer of citalopram, meaning it contains the more pharmacologically active component of citalopram. Both medications work by blocking the reuptake of serotonin in the brain, increasing serotonin availability at synapses to improve mood and reduce anxiety symptoms.

Mechanism of Interaction

The interaction between citalopram and escitalopram occurs through additive pharmacological effects on serotonin reuptake inhibition. Both drugs block the serotonin transporter (SERT) with similar mechanisms, leading to excessive serotonin accumulation when used together. Since escitalopram is derived from citalopram and represents its most active component, combining these medications essentially creates a double dose effect on serotonin systems, significantly increasing the risk of serotonin toxicity without providing additional therapeutic benefit.

Risks and Symptoms

The primary risk of combining citalopram and escitalopram is serotonin syndrome, a potentially life-threatening condition characterized by altered mental status, autonomic instability, and neuromuscular abnormalities. Patients may experience symptoms including agitation, confusion, rapid heart rate, high blood pressure, dilated pupils, muscle rigidity, and hyperthermia. Additional risks include increased incidence of common SSRI side effects such as nausea, diarrhea, headache, sexual dysfunction, and sleep disturbances. The combination also increases the risk of QT interval prolongation, particularly with citalopram, which can lead to dangerous cardiac arrhythmias.

Management and Precautions

Citalopram and escitalopram should never be prescribed together. When switching between these medications, a washout period is typically not required since they have similar mechanisms, but the transition should be carefully managed by a healthcare provider. If a patient is accidentally taking both medications, one should be discontinued immediately under medical supervision. Healthcare providers should monitor for signs of serotonin syndrome during any SSRI transitions and educate patients about recognizing symptoms. When switching from citalopram to escitalopram or vice versa, dose adjustments may be necessary as escitalopram is typically prescribed at half the dose of citalopram due to its increased potency.

Citalopram interactions with food and lifestyle

Alcohol: Citalopram may increase the sedative effects of alcohol. Patients should avoid or limit alcohol consumption while taking citalopram as it can worsen depression symptoms and increase the risk of drowsiness, dizziness, and impaired judgment. Grapefruit: While not a major interaction, grapefruit juice may slightly increase citalopram levels in the blood. Patients should consult their healthcare provider about grapefruit consumption. MAO inhibitors and certain foods: Patients taking citalopram should avoid tyramine-rich foods (aged cheeses, cured meats, fermented foods) if they have recently discontinued or are transitioning from MAO inhibitors, though this is more relevant during the washout period between medications.

Escitalopram interactions with food and lifestyle

Alcohol: Escitalopram may increase the effects of alcohol and impair mental and motor skills. Patients should avoid or limit alcohol consumption while taking escitalopram as recommended by clinical guidelines and major drug databases. The combination can increase sedation, dizziness, and may worsen depression symptoms.