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: To report a sinus bradycardia induced by metoprolol and terbinafine drug - drug interaction and its management .
### Output Text:
To report a sinus bradycardia induced by <span class="chemical">metoprolol</span> and <span class="chemical">terbinafine</span> drug - drug interaction and its management . 