538
In this case, unlike those previously reported, hyponatremia recurred 5 months after switching from citalopram to mirtazapine, which is believed to be a safe antidepressant.
 hyponatremia: Effect; switching from citalopram to mirtazapine: Treatment; citalopram: Treatment.Drug; mirtazapine: Treatment.Drug; 5 months: Treatment.Time_elapsed
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: adverse event 
  Option: Treatment.Freq, Subject.Population, Combination.Drug, Subject.Gender, Treatment.Duration, Subject, Effect, Treatment, Treatment.Disorder, Subject.Disorder, Treatment.Route, Subject.Race, Treatment.Time_elapsed, Treatment.Dosage, Subject.Age, Treatment.Drug 
Text: {0} 
Answer:
 hyponatremia: Effect; switching from citalopram to mirtazapine: Treatment; citalopram: Treatment.Drug; mirtazapine: Treatment.Drug; 5 months: Treatment.Time_elapsed