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: In the bupivacaine groups , epinephrine caused fewer prodysrhythmic effects than without bupivacaine .
### Output Text:
In the <span class="chemical">bupivacaine</span> groups , <span class="chemical">epinephrine</span> caused fewer prodysrhythmic effects than without <span class="chemical">bupivacaine</span> . 