Yesterday the US Food and Drug Administration announced that Citalopram hydrobromide, also known as Celexa, should not be administered at doses over 40 mg per day, because it can trigger abnormal electrical activity in the heart, leading to potentially fatal heart rhythm problems (including Torsade de Pointes).
Celexa is an SSRI (selective serotonin reuptake inhibitors) class of antidepressant. It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance. However, the Agency added that doses above 40mg per day do not benefit in the treatment of depression.
A citalopram drug label used to state that some patients may need 60 mg per day, however with this new warning, this is now not recommended. The drug label has now been modified to include usage recommendations and the new drug dosage, as well as details on the risk for QT interval prolongation and Torsade de Pointes.
Torsade de pointes is an uncommon and distinctive form of polymorphic ventricular tachycardia (VT) characterized by a gradual change in the amplitude and twisting of the QRS complexes around the isoelectric line (see the image below). Torsade de pointes, often referred to as torsade, is associated with a prolonged QT interval, which may be congenital or acquired. Torsade usually terminates spontaneously but frequently recurs and may degenerate into ventricular fibrillation.
Alterations in the heart’s electrical activity (prolongation of the QT interval) may especially affect those with existing heart conditions, as well as patients who are prone to low levels of blood potassium and magnesium.
Celexa will now be available in tablet form in doses of 10 mg, 20 mg, and 40 mg. It is also available as a 10 mg/5mL oral solution.
The FDA is telling medical professionals to not prescribe citalopram at doses greater than 40 mg per day, because of dose dependent QT interval prolongation risk. Also, patients with congenital long QT syndrome should not be prescribed citalopram.
Patients with bradyarrhythmias, heart failure, or predisposition to hypomagnesemia or hypokalemia because of concomitant illness or medications, have a greater chance of developing Torsade de Pointes.
Hypomagnesemia and hypokalemia should be effectively treated before prescribing citalopram. Test for electrolytes as clinically indicated.
For patients with bradyarrhythmias, congestive heart failure, or those on concomitant drugs that prolong QT interval, consider ECG monitoring more frequently.
For those with hepatic impairment, aged 60+ years, who are CYP 2C19 poor metabolizers, or who are taking concomitant Tagamet (Cimetidine) – the maximum recommended dose is 20 mg per day.
For those with mild or moderate renal impairment, dose adjustments are not necessary.
Tell patients who are taking citalopram to contact a healthcare professional if they have signs and symptoms of abnormal heart rhythm or heart rate.
FDA is also informing patients that if they are taking citalopram, not to change your dose or stop taking it without talking to your doctor first. If you stop taking citalopram abruptly you may experience undesirable side effects.
Patients on doses above 40 mg per day should talk to their physician about altering the dosage. If you have shortness of breath, dizziness, fainting, or irregular heartbeat, and you are on citalopram, get immediate medical attention.
Doctors of patients on citalopram may sometimes order an ECG or EKG to monitor heart rate and rhythm.
Those on citalopram should read its Medication Guide carefully, and discuss any questions with their doctor, and report any adverse effects as soon as possible.