Cipralex Active Molecule
The active molecule in Cipralex is escitalopram (escitalopram oxalate), which is the therapeutically active S-enantiomer of the racemic compound citalopram 1, 2.
Chemical Identity and Mechanism
Escitalopram is a highly selective serotonin reuptake inhibitor (SSRI) that works by potently inhibiting the serotonin transporter protein in the central nervous system 3, 1. This selective inhibition increases serotonergic activity by preventing serotonin reuptake into presynaptic nerve terminals.
Key Distinguishing Features:
Enantiomeric specificity: Escitalopram is the isolated S-enantiomer extracted from racemic citalopram (RS-citalopram), making it approximately 8 times more potent than its metabolites in inhibiting serotonin reuptake 3
High selectivity: It demonstrates minimal effects on norepinephrine and dopamine reuptake, with very low affinity for other receptor systems including 5-HT1A, 5-HT2A, dopamine, adrenergic, histamine, GABA, muscarinic cholinergic, and benzodiazepine receptors 3
Clinical Formulation
The drug contains escitalopram hydrobromide as the active pharmaceutical ingredient 3. The inactive ingredients include copovidone, corn starch, croscarmellose sodium, lactose monohydrate, magnesium stearate, hypromellose, microcrystalline cellulose, polyethylene glycol, and titanium dioxide, with iron oxides used as coloring agents in certain tablet strengths 3.
Important Pharmacokinetic Considerations:
The metabolism of escitalopram occurs primarily through CYP3A4 and CYP2C19 enzymes 3. This is clinically relevant because CYP2C19 poor metabolizers show 68% higher peak concentrations and 107% higher drug exposure compared to normal metabolizers, which may necessitate dose adjustments 3.