Annotation of Health Canada Santé Canada (HCSC) label information
for citalopram
and CYP2C19
Summary
The product monograph for citalopram recommends that patients who are CYP2C19 poor metabolizers receive an initial dose of 10 mg daily during the first two weeks of treatment, and should not receive a dose of greater than 20 mg/day. However, it makes no statements regarding genetic testing of CYP2C19 prior to treatment.
Annotation
Citalopram is indicated for treatment of depressive illness. Excerpts from the citalopram product monograph:
CYP2C19 Poor Metabolisers: An initial dose of 10 mg daily during the first two weeks of treatment is recommended for patients who are known to be poor metabolisers of CYP2C19. The dose may be increased to a maximum of 20 mg daily depending on individual patient response.
In vitro studies indicated that the biotransformation of citalopram to its demethyl metabolites depends on both CYP2C19 and CYP3A4, with a small contribution from CYP2D6. An initial dose of 10 mg is recommended for known poor metabolisers of CYP2C19.
For the complete product monograph text with sections containing pharmacogenetic information highlighted, see the citalopram product monograph.
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