Fatal dose not known. Patients have survived ingestion of up to 2 g citalopram. The effects will be potentiated by alcohol taken at the same time. Potential interaction with tricyclic antidepressants and MAOIs.
Nausea, vomiting, sweating, tachycardia, drowsiness, coma, dystonia, convulsions, hyperventilation and hyperpyrexia have been reported. Cardiac features that have been observed include nodal rhythm, prolonged QT intervals and wide QRS complexes. Prolonged bradycardia with severe hypotension and syncope has also been reported.
Rarely, features of the "serotonin syndrome" may occur in severe poisoning. This includes alteration of mental status, neuromuscular hyperactivity and autonomic instability. There may be hyperpyrexia and elevation of serum creatine kinase. Rhabdomyolysis is rare.
Management should be symptomatic and supportive and include the maintenance of a clear airway and monitoring of cardiac and vital signs until stable. Consider oral activated charcoal in adults and children who have ingested more than 5 mg/kg body weight within 1 hour. Observe for a minimum of 4 hours due to long half life of citalopram.
Control convulsions with intravenous diazepam if they are frequent or prolonged. An ECG should be taken.