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: Cardiac arrest after intravenous metoclopramide - a case of five repeated injections of metoclopramide causing five episodes of cardiac arrest .
### Output Text:
Cardiac arrest after intravenous <span class="chemical">metoclopramide</span> - a case of five repeated injections of <span class="chemical">metoclopramide</span> causing five episodes of cardiac arrest . 