pms-Citalopram Overdosage

In clinical trials with racemic citalopram, there were no reports of fatal citalopram overdoses of up to 2000 mg. All patients recovered. Events of torsade de pointes have been reported during overdose with citalopram hydrobromide during post-market use (see Dosage & Administration; QT Prolongation under Contraindications; Cardiovascular: QT Prolongation and Torsades de Pointes under Precautions; Post-Market Adverse Drug Reactions under Adverse Reactions; Interactions). When specified, these overdoses were in the range of 800-1000 mg.
Comprehensive clinical data on citalopram overdose are limited and many cases involve concomitant overdoses of other drugs and/or alcohol. Fatal cases of citalopram overdose have been reported with citalopram alone; however, the majority of fatal cases have involved overdose with concomitant medications. Post-marketing reports of drug overdoses involving citalopram have included fatalities with citalopram alone as well as non-fatal overdoses of up to 5200 mg.
Although most patients recovered without sequelae, 3 fatalities with known overdoses of racemic citalopram alone have been reported in the literature (doses of 2800 mg, 2880 mg, and 3920 mg).
Fatal cases of serotonin syndrome have been reported in patients who took overdoses of moclobemide and citalopram hydrobromide (see Neurologic: Serotonin Syndrome/Neuroleptic Malignant Syndrome (NMS)-Like Events under Precautions). The plasma concentrations of moclobemide were between 16 and 90 mg/L (therapeutic range: 1 to 3 mg/L) and those of citalopram hydrobromide between 0.3 and 1.7 mg (therapeutic concentration: 0.3 mg/L). This indicates that a relatively low dose of citalopram hydrobromide, given with an overdose of moclobemide represents a serious risk for the patient.
Symptoms of Overdose: The following symptoms have been seen in reported overdose of citalopram: agitation, atrial and ventricular arrhythmia, bradycardia, bundle branch block, cardiac arrest, confusion, convulsion, coma, cyanosis, dizziness, ECG changes, hyperventilation, hypotension, hypertension, loss of consciousness, mydriasis, nausea, QRS prolongation, QT prolongation, rhabdomyolysis, seizure, serotonin syndrome, somnolence, stupor, sweating, tachycardia, torsade de pointes, tremor, and vomiting.
Management of Overdose: Establish and maintain an airway to ensure adequate ventilation and oxygenation. Gastric lavage and use of activated charcoal should be considered. Gastric lavage should be carried out as soon as possible after oral ingestion. Cardiac and vital sign monitoring are recommended, along with general symptomatic and supportive measures. There are no specific antidotes for citalopram hydrobromide.
ECG monitoring is advisable in case of overdose.
Due to the large volume of distribution of citalopram hydrobromide, forced diuresis, dialysis, hemoperfusion and exchange transfusion are unlikely to be of benefit.
In managing overdosage, the possibility of multiple drug involvement must be considered.