Is there is any API for getting the label changes for a list of drugs.
I have been searching for APIs and RSS feeds with no luck.
As of right now, SPL (structured product labels) are not part of the openFDA list of APIs for drugs (https://open.fda.gov/drug/event/ - note how "product labels" is greyed out). You can learn more about the SPL standard, guidance, etc. directly from the FDA at http://www.fda.gov/ForIndustry/DataStandards/StructuredProductLabeling/default.htm.
While you wait for the openFDA project to serve SPLs, there is a robust (and actively improved - latest update was February 2014) website (with web services!) maintained by HHS/NIH/NLM called DailyMed. Information on DailyMed web services can be found at http://dailymed.nlm.nih.gov/dailymed/help.cfm#webservices .
From my intermediate knowledge of SPLs, they are versioned by a unique GUID called "set IDs" as well as an addition "SPL version". There is an API endpoint for getting the history of a specific SPL Set ID as well as an API endpoint for finding the drug record (including set ID) in the first place.
Also note that the DailyMed site maintains an RSS feed for each set ID (such as
http://dailymed.nlm.nih.gov/dailymed/labelrss.cfm?setid=c5fdde91-1989-4dd2-9129-4f3323ea2962) as well as an RSS feed for all changes in the past 7 days (
Hope this helps!