In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Eight patients had cardiac manifestations that were life - threatening in five while taking psychotropic drugs , either phenothiazines or tricyclic antidepressants .
### Output Text:
Eight patients had cardiac manifestations that were life - threatening in five while taking psychotropic drugs , either <span class="chemical">phenothiazines</span> or tricyclic antidepressants . 