Name two circumstances when a selective serotonin reuptake inhibitor (SSRI) overdose may be potentially dangerous.

1. massive overdose 
2. citalopram (Celexa) overdose which can cause QT prolongation and seizures 

Otherwise, SSRI overdoses are generally benign. 


Source

Peer VIII: Physcian's Evaluation and Educational Review in Emergency Medicine, American College of Emergency Physicians