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Citalopram is associated with a dose dependant QT interval prolongation.
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The maximum dose in healthy adults is now 40mg daily.
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In the elderly and with patients with reduced hepatic function, the maximum dose is 20mg daily.
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Citalopram is contraindicated in patients with known QT interval prolongation or congenital long QT syndrome.
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The use of citalopram with other medicines known to prolong the QT interval is contraindicated.
Caution is advised in patients at higher risk of developing Torsade de Pointes, for example those with congestive heart failure, recent M.I, bradyarrhythmias or predisposition to hypokalemia and hypomagnesemia because of concomitant illness or medicines.
Some medicines associated with the QT prolongation (this list is not exhaustive) include:
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Antibiotics
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Antivirals
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· Quinidine
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Antipsychotics**
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· Azithromycin
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· Nelfinavir
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· Amiodarone
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· Risperidone
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· Clarithromycin
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· Sotalol
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· Fluphenazine
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· Erythromycin
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Antimalarials
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· Haloperidol
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· Roxithromycin
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· Chloroquine
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Antidepressants
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· Clozapine
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· Metronidazole (with alcohol)
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· Mefloquine
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· Amitriptyline
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· Pimozide
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· Moxifloxan
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· Clomipramine
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· Chlorpromazine
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Anaesthetics
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· Dosulepin
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Antifungals
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· Halothane
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· Doxepin
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Others
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· Fluconazole (in cirrhosis)
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· Imipramine
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· Methadone
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** These are examples, all have potential.
You will note that this includes antipsychotics with which citalopram will be occasionally prescribed. This comes within the contra-indication and our advice is that these patients should be reviewed.
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Patients who are on higher doses of citalopram (above 40mg or 20mg in the elderly) will need to be identified, reviewed and gradually reduced. These patients may require follow up appointments to monitor progress and some may require further advice from or referral to a consultant psychiatrist.
Patients on interacting medicines should be reviewed and where necessary or appropriate, consideration should be given to switching to alternative antidepressants. It should be noted that cases of QT interval prolongation have also been reported with some other selective serotonin reuptake inhibitors (SSRIs) including escitalopram.
For some patients, who are stable, it may be reasonable to maintain on citalopram and this should be clearly documented in the patient’s notes.
Citalopram remains a suitable and safe antidepressant, within its licensed therapeutic indications and dosage for patients without contra-indications and who are not taking interacting medicines.
In other patients, alternative SSRIs such as fluoxetine or sertraline would be suitable alternatives to citalopram.
Update by: Nigel Barnes, director of pharmacy and medicines management
