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: Side effects attributable to mazindol included decreased appetite ( 36 % ) , dry mouth ( 10 % ) , behavioral change ( 22 % ) , and gastrointestinal symptoms ( 18 % ) ; mazindol dosage was reduced in 43 % of patients .
### Output Text:
Side effects attributable to <span class="chemical">mazindol</span> included decreased appetite ( 36 % ) , dry mouth ( 10 % ) , behavioral change ( 22 % ) , and gastrointestinal symptoms ( 18 % ) ; <span class="chemical">mazindol</span> dosage was reduced in 43 % of patients . 