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: OBJECTIVE : To describe a case of flecainide - induced delirium associated with a pharmacokinetic drug interaction with paroxetine .
### Output Text:
OBJECTIVE : To describe a case of <span class="chemical">flecainide</span> - induced delirium associated with a pharmacokinetic drug interaction with <span class="chemical">paroxetine</span> . 