- Metabolism: Mainly hepatic. Escitalopram undergoes N-demethylation to S-demethylcitalopram (S-DCT) and S-didemethylcitalopram (S-DDCT). CYP3A4 and CYP2C19 are the enzymes responsible for this N-demethylation reaction. Route of Elimination: Following oral administrations of escitalopram, the fraction of drug recovered in the urine as escitalopram and S-demethylcitalopram (S-DCT) is about 8% and 10%, respectively. The oral clearance of escitalopram is 600 mL/min, with approximately 7% of that due to renal clearance. Escitalopram is metabolized to S-DCT and S-didemethylcitalopram (S-DDCT). Half Life: 27-32 hours
- Uses/Sources: Labeled indications include major depressive disorder (MDD) and generalized anxiety disorder (GAD). Unlabeled indications include treatment of mild dementia-associated agitation in nonpsychotic patients.
- Symptoms: Signs of overdose include convulsions, coma, dizziness, hypotension, insomnia, nausea, vomiting, sinus tachycardia, somnolence, and ECG changes (including QT prolongation).
- Treatment: Establish and maintain an airway to ensure adequate ventilation and oxygenation. Gastric evacuation by lavage and use of activated charcoal should be considered. Careful observation and cardiac and vital sign monitoring are recommended, along with general symptomatic and supportive care. Due to the large volume of distribution of escitalopram, forced diuresis, dialysis, hemoperfusion, and exchange transfusion are unlikely to be of benefit. There are no specific antidotes for Escitalopram. (L1712)
- Route of Exposure: The absolute bioavailability of citalopram is about 80% relative to an intravenous dose.
Mechanism of Action
|Target Name||Mechanism of Action||References|
Muscarinic acetylcholine receptor M1
Alpha-1A adrenergic receptor
Sodium-dependent dopamine transporter
Sodium-dependent noradrenaline transporter
Histamine H1 receptor
|Sodium-dependent serotonin transporter||The antidepressant, antiobsessive-compulsive, and antibulimic actions of escitalopram are presumed to be linked to its inhibition of CNS neuronal uptake of serotonin. Escitalopram blocks the reuptake of serotonin at the serotonin reuptake pump of the neuronal membrane, enhancing the actions of serotonin on 5HT1A autoreceptors. SSRIs bind with significantly less affinity to histamine, acetylcholine, and norepinephrine receptors than tricyclic antidepressant drugs.||