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: Review of this and previously reported cases indicates the need for early diagnosis of amiodarone pneumonitis , immediate withdrawal of amiodarone , and prompt but continued steroid therapy to ensure full recovery .
### Output Text:
Review of this and previously reported cases indicates the need for early diagnosis of <span class="chemical">amiodarone</span> pneumonitis , immediate withdrawal of <span class="chemical">amiodarone</span> , and prompt but continued <span class="chemical">steroid</span> therapy to ensure full recovery . 