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: CASE SUMMARY : A 42 - year - old white man developed acute hypertension with severe headache and vomiting 2 hours after the first doses of amisulpride 100 mg and tiapride 100 mg .
### Output Text:
CASE SUMMARY : A 42 - year - old white man developed acute hypertension with severe headache and vomiting 2 hours after the first doses of <span class="chemical">amisulpride</span> 100 mg and <span class="chemical">tiapride</span> 100 mg . 