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: Here , we describe the clinical presentation and review the relevant literature on amlodipine and dysguesia .
### Output Text:
Here , we describe the clinical presentation and review the relevant literature on <span class="chemical">amlodipine</span> and dysguesia . 