Citalopram

Class

• • Furancarbonitrile SSRI

Indications

• Major depression

  • Anxiety, panic disorder, ADHD, PMDD, Body dysmorphic disorder and OCD

• Diabetic neuropathy

• Premature ejaculation

• Post-stroke pathological crying

  • Migraines

• Hot flashes

Administration/Absorption

• • Oral

  • Single daily dose

  • Bioavailability is 80% following oral administration

Dosage

Distribution

• • Volume of distribution 12 L/kg

Mechanism

• • The antidepressant, antiobsessive-compulsive, and antibulimic actions of Citalopram are presumed to be linked to its inhibition of CNS neuronal uptake of serotonin

  • Citalopram blocks the reuptake of serotonin at the serotonin reuptake pump of the neuronal membrane, enhancing the actions of serotonin on 5HT_1A autoreceptors

  • Has only very weak effects on norepinephrine and dopamine neuronal reuptake

  • Has no significant affinity for adrenergic (alpha1, alpha2, beta), cholinergic, GABA, dopaminergic, histaminergic, serotonergic (5HT_1A, 5HT_1B, 5HT₂), or benzodiazepine receptors

    • Antagonism of such receptors has been hypothesized to be associated with various anticholinergic, sedative, and cardiovascular effects for other psychotropic drugs

  • Citalopram does not inhibit monoamine oxidase.

Excretion

• • Half-life 35 hrs

  • The systemic clearance of citalopram was 330 mL/min, with approximately 20% of that due to renal clearance

  • Citalopram is metabolized to demethylcitalopram (DCT), didemethylcitalopram (DDCT), citalopram-N-oxide, and a deaminated propionic acid derivative

Side effects

• • The chronic administration of Citalopram was found to downregulate brain norepinephrine receptors, as has been observed with other drugs effective in the treatment of major depressive disorder

  • Common side effects:

    • drowsiness, insomnia, nausea, weight changes, frequent urination, decreased sex drive, anorgasmia, dry mouth, increased sweating, trembling, diarrhea, excessive yawning, and fatigue

  • Less common side effects:

    • bruxism, vomiting, cardiac arrhythmia, blood pressure changes, dilated pupils, anxiety, mood swings, headache, and dizziness

  • Rare side effects:

    • convulsions, hallucinations, and severe allergic reactions

• SSRI discontinuation syndrome

Interactions

Contraindications