Citalopram (Dosage)

Citalopram is an antidepressant drug used in various mental illnesses such as depression, anxiety or obsessive-compulsive disorder. It is metabolized by CYP2C19, so the presence of certain alleles may condition tolerability and the development of adverse effects.

Citalopram is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) group. It has no effect on noradrenaline, dopamine or GABA reuptake.


Hypersensitivity. Citalopram is contraindicated during treatment with MAOI antidepressants including selegiline at doses >10mg/day. Treatment with citalopram can be started 14 days after discontinuation of an irreversible MAOI or the specified time after discontinuation of a reversible MAOI; and treatment with MAOI antidepressants can be started 7 days after discontinuation of treatment with citalopram. Concomitant treatment with pimozide and/or linezolid (except with close blood pressure control) is contraindicated.

The use of citalopram is contraindicated in patients with a history of elongated cardiac QT interval or congenital long QT segment syndrome, as well as in treatment with drugs that prolong the QT interval.


Precautions should be taken in patients with severe renal insufficiency, hepatic insufficiency, manic crisis, history of bleeding disorders, patients undergoing electroconvulsive therapy (ECT), diabetics and psychotics. Extreme caution should also be exercised if citalopram is prescribed to patients at risk of developing Torsade de Pointes, e.g., patients with congestive heart failure, myocardial infarction, bradyarrhythmias or predisposition to hypokalemia or hypomagnesemia due to disease or medication; angle-closure glaucoma or history of glaucoma.

Avoid prescribing citalopram in unstable epilepsy and monitor in controlled epilepsy. Discontinue treatment if seizures appear or their frequency increases.

Do not use in children under 18 years of age.

At the beginning of treatment may increase anxiety symptoms (paradoxical anxiety), start with lower doses. Risk of hyponatremia. Caution and monitoring in patients with history of suicide or significant degree of suicidal ideation prior to initiation of treatment. Akathisia/psychomotor agitation may appear in the first weeks, evaluate its use.


Increased appetite, decreased appetite, weight gain, weight loss, anorexia; agitation, nervousness, decreased libido, anxiety, confusion, sleep disturbances, attention disturbance, abnormal orgasms (women), abnormal dreams, apathy; drowsiness, insomnia, headache, tremor, dizziness, paresthesia, migraine, amnesia; abnormal accommodation, visual disturbance; tinnitus; palpitations, tachycardia; hypertension, orthostatic hypotension; yawning, rhinitis, sinusitis; dry mouth, nausea, diarrhea, constipation, vomiting, dyspepsia, abdominal pain, flatulence, increased salivation, taste abnormalities; increased sweating, pruritus, rash, myalgia, arthralgia; urination disorder, polyuria; impotence, ejaculation disorder, ejaculatory insufficiency, dysmenorrhea (women); asthenia, fatigue.


Warnings and precautions with buspirone At the pharmacodynamic level, cases of serotonergic syndrome have been reported.

Serotonergic effects increased with lithium or tryptophan.

Avoid taking citalopram with alcohol.

Warnings and precautions with: drugs that lower the seizure threshold, e.g. antidepressants (tricyclics, SSRIs), neuroleptics (phenothiazines, thioxanthines and butyrophenones), mefloquine, bupropion and tramadol.

Citalopram increases the concentration of: desimipramine and metoprolol; in these cases adjust the dose.

Citalopram concentration is increased with: cimetidine, omeprazole, esomeprazole, fluvoxamine, lansoprazole, ticlopidine; in these cases adjust the dose of citalopram.

Do not use citalopram together with drugs with serotonergic effect such as sumatriptan or other triptans, tramadol and tryptophan; neither together with St. John's wort. Caution in concomitant use of oral anticoagulants, drugs that affect platelet function such as NSAIDs, ASA, dipyridamole and ticlopidine, or others (e.g. atypical antipsychotics, phenothiazines, tricyclic antidepressants) that increase the risk of bleeding. Avoid abrupt discontinuation of treatment with citalopram.


  • Calton®
  • Citalvir® Citalvir® Citalvir® Citalvir® Citalvir® Citalvir
  • Prisdal® Prisdal® Prisdal® Prisdal® Prisdal® Prisdal® Prisdal
  • Relapaz®
  • Seregra®
  • Seropram®

Genes analyzed



Bousman CA, Stevenson JM, Ramsey LB, et al.Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2D6, CYP2C19, CYP2B6, SLC6A4, and HTR2A Genotypes and Serotonin Reuptake Inhibitor Antidepressants. Clin Pharmacol Ther. 2023 Jul;114(1):51-68. doi: 10.1002/cpt.2903. Epub 2023 May 30.

Brouwer JMJL, Nijenhuis M, Soree B, et al.Dutch Pharmacogenetics Working Group (DPWG) guideline for the gene-drug interaction between CYP2C19 and CYP2D6 and SSRIs. Eur J Hum Genet. 2022 Oct;30(10):1114-1120.

Campos AI, Byrne EM, Mitchell BL, et al.Impact of CYP2C19 metaboliser status on SSRI response: a retrospective study of 9500 participants of the Australian Genetics of Depression Study. Pharmacogenomics J. 2022 Mar;22(2):130-135.

Wong WLE, Fabbri C, Laplace B, et al.The Effects of CYP2C19 Genotype on Proxies of SSRI Antidepressant Response in the UK Biobank. Pharmaceuticals (Basel). 2023 Sep 11;16(9):1277.

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