The concurrent use of a tricyclic antidepressant and 
lithium can be beneficial in some patients. However, some patients may rarely develop adverse effects, a few of them severe. Cases of neurotoxicity, 
serotonin syndrome and neuroleptic malignant 
syndrome have been reported. 
 If both drugs are used be alert for any evidence of neurotoxicity . Additive QT-prolonging effects also possible, see drugs that prolong the QT interval.