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: Six stable psychiatric outpatients with hyperprolactinemia and amenorrhea / oligomenorrhea associated with their neuroleptic medications were treated with bromocriptine .
### Output Text:
Six stable psychiatric outpatients with hyperprolactinemia and amenorrhea / oligomenorrhea associated with their <span class="chemical">neuroleptic medications</span> were treated with <span class="chemical">bromocriptine</span> . 