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: CONCLUSION : No exaggerated adrenergic response was detected when dobutamine was administered to patients with cocaine - related chest pain .
### Output Text:
CONCLUSION : No exaggerated adrenergic response was detected when <span class="chemical">dobutamine</span> was administered to patients with <span class="chemical">cocaine</span> - related chest pain . 