ClassIndications
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 5HT1A 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 (5HT1A, 5HT1B, 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:
- Rare side effects:
- SSRI discontinuation syndrome
Interactions
Contraindications
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