Citalopram (Page 2 of 8)

5.2 QT-Prolongation and Torsade de Pointes

Citalopram causes dose dependent QTc prolongation an ECG abnormality that has been associated with Torsade de Pointes (TdP), ventricular tachycardia, and sudden death, all of which have been observed in post marketing reports for citalopram [see Adverse Reactions 6.2)].

Because of the risk of QTc prolongation at higher citalopram doses, it is recommended that citalopram not be given at doses above 40 mg once daily [see Dosage and Administration (2.1), Clinical Pharmacology (12.2)].

Citalopram should be avoided in patients with congenital long QT syndrome, bradycardia, hypokalemia or hypomagnesemia, recent acute myocardial infarction, or uncompensated heart failure unless the benefits outweigh the risks for a particular patient. Citalopram should also be avoided in patients who are taking other drugs that prolong the QTc interval [see Drug Interactions (7)]. Such drugs include Class 1A (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmic medications, antipsychotic medications (e.g., chlorpromazine, thioridazine), antibiotics (e.g., gatifloxacin, moxifloxacin), or any other class of medications known to prolong the QTc interval (e.g., pentamidine, levomethadyl acetate, methadone).

The citalopram dose should be limited in certain populations. The maximum dose should be limited to 20 mg once daily in patients who are CYP2C19 poor metabolizers or those patients receiving concomitant cimetidine or another CYP2C19 inhibitor, since higher citalopram exposures would be expected. The maximum dose should also be limited to 20 mg once daily in patients with hepatic impairment and in patients who are greater than 60 years of age because of expected higher exposures [see Dosage and Administration (2.3, 2.4), Drug Interactions (7), Use in Specific Populations (8.5), Clinical Pharmacology (12.3)].

Electrolyte and/or ECG monitoring is recommended in certain circumstances. Patients being considered for treatment with Citalopram who are at risk for significant electrolyte disturbances should have baseline serum potassium and magnesium measurements with periodic monitoring. Hypokalemia (and/or hypomagnesemia) may increase the risk of QTc prolongation and arrhythmia and should be corrected prior to initiation of treatment and periodically monitored. ECG monitoring is recommended in patients for whom Citalopram use is not recommended unless the benefits clearly outweigh the risks for a particular patient (see above). These include those patients with the cardiac conditions noted above, and those taking other drugs that may prolong the QTc interval.

Discontinue Citalopram in patients who are found to have persistent QTc measurements >500 ms. If patients taking Citalopram experience symptoms that could indicate the occurrence of cardiac arrhythmias, e.g., dizziness, palpitations, or syncope, the prescriber should initiate further evaluation, including cardiac monitoring.

5.3 Serotonin Syndrome

SSRIs, including Citalopram, can precipitate serotonin syndrome, a potentially life-threatening condition. The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. John’s Wort) and with drugs that impair metabolism of serotonin, i.e., MAOIs [see Contraindications (4), Drug Interactions (7)]. Serotonin syndrome can also occur when these drugs are used alone. Symptoms of serotonin syndrome were noted in 0.1% of MDD patients treated with Citalopram in premarketing clinical trials.

Serotonin syndrome signs and symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).

The concomitant use of Citalopram with MAOIs is contraindicated. In addition, do not initiate Citalopram in a patient being treated with MAOIs such as linezolid or intravenous methylene blue. No reports involved the administration of methylene blue by other routes (such as oral tablets or local tissue injection). If it is necessary to initiate treatment with an MAOI such as linezolid or intravenous methylene blue in a patient taking Citalopram, discontinue Citalopram before initiating treatment with the MAOI [see Contraindications (4), Drug Interactions (7)].

Monitor all patients taking Citalopram for the emergence of serotonin syndrome. Discontinue treatment with Citalopram and any concomitant serotonergic agents immediately if the above symptoms occur and initiate supportive symptomatic treatment. If concomitant use of Citalopram with other serotonergic drugs is clinically warranted, inform patients of the increased risk for serotonin syndrome and monitor for symptoms.

5.4 Increased Risk of Bleeding

Drugs that interfere with serotonin reuptake inhibition, including Citalopram, increase the risk of bleeding events. Concomitant use of aspirin, nonsteroidal anti-inflammatory drugs (NSAIDS), other antiplatelet drugs, warfarin, and other anticoagulants may add to this risk. Case reports and epidemiological studies (case-control and cohort design) have demonstrated an association between use of drugs that interfere with serotonin reuptake and the occurrence of gastrointestinal bleeding. Bleeding events related to drugs that interfere with serotonin reuptake have ranged from ecchymosis, hematoma, epistaxis, and petechiae to life-threatening hemorrhages.

Inform patients about the increased risk of bleeding associated with the concomitant use of Citalopram and antiplatelet agents or anticoagulants. For patients taking warfarin, carefully monitor the international normalized ratio [see Drug Interactions (7)].

5.5 Activation of Mania or Hypomania

In patients with bipolar disorder, treating a depressive episode with Citalopram or another antidepressant may precipitate a mixed/manic episode. In controlled clinical trials, patients with bipolar disorder were excluded; however, symptoms of mania or hypomania were reported in 0.1% of undiagnosed patients treated with Citalopram. Prior to initiating treatment with Citalopram, screen patients for any personal or family history of bipolar disorder, mania, or hypomania [see Dosage and Administration (2.2)].

5.6 Discontinuation Syndrome

Adverse reactions after discontinuation of serotonergic antidepressants, particularly after abrupt discontinuation, include: nausea, sweating, dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paresthesia, such as electric shock sensations), tremor, anxiety, confusion, headache, lethargy, emotional lability, insomnia, hypomania, tinnitus, and seizures. A gradual reduction in dosage rather than abrupt cessation is recommended whenever possible [see Dosage and Administration (2.6)].

5.7 Seizures

Citalopram has not been systematically evaluated in patients with seizure disorders. Patients with a history of seizures were excluded from clinical studies. In clinical trials of Citalopram, seizures occurred in 0.3% of patients treated with Citalopram (a rate of one patient per 98 years of exposure) and 0.5% of patients treated with placebo (a rate of one patient per 50 years of exposure). Citalopram should be prescribed with caution in patients with a seizure disorder.

5.8 Angle-closure Glaucoma

The pupillary dilation that occurs following use of many antidepressant drugs, including Citalopram, may trigger an angle closure attack in a patient with anatomically narrow angles who does not have a patent iridectomy. Avoid use of antidepressants, including Citalopram, in patients with untreated anatomically narrow angles.

5.9 Hyponatremia

Hyponatremia may occur as a result of treatment with SSRIs, including Citalopram. Cases of serum sodium lower than 110 mmol/L have been reported. Signs and symptoms of hyponatremia include headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness, which may lead to falls. Signs and symptoms associated with more severe and/or acute cases have included hallucination, syncope, seizure, coma, respiratory arrest, and death. In many cases, this hyponatremia appears to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH).

In patients with symptomatic hyponatremia, discontinue Citalopram and institute appropriate medical intervention. Elderly patients, patients taking diuretics, and those who are volume-depleted may be at greater risk of developing hyponatremia with SSRIs [see Use in Specific Populations (8.5)].

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