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: Our findings indicate that sustained - release nifedipine is useful for hypertensive psoriatic patients under long - term treatment with cyclosporin A , but that these patients should be monitored for gingival hyperplasia .
### Output Text:
Our findings indicate that sustained - release <span class="chemical">nifedipine</span> is useful for hypertensive psoriatic patients under long - term treatment with <span class="chemical">cyclosporin A</span> , but that these patients should be monitored for gingival hyperplasia . 