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: We present a case of a 5 - year - old child with cerebral palsy and seizure disorder , receiving clonidine for restlessness , who presented for placement of a baclofen pump .
### Output Text:
We present a case of a 5 - year - old child with cerebral palsy and seizure disorder , receiving <span class="chemical">clonidine</span> for restlessness , who presented for placement of a <span class="chemical">baclofen</span> pump . 