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: Abnormal involuntary movements appeared in the mouth , tongue , neck and abdomen of a 64 - year - old male patient after he took metoclopramide for gastrointestinal disorder in a regimen of 30 mg per day for a total of about 260 days .
### Output Text:
Abnormal involuntary movements appeared in the mouth , tongue , neck and abdomen of a 64 - year - old male patient after he took <span class="chemical">metoclopramide</span> for gastrointestinal disorder in a regimen of 30 mg per day for a total of about 260 days . 