Halperin says that it may take wide use of the drug to be absolutely sure there are no problems.

FORBES: Replacing Coumadin

"They want to be absolutely sure what they're dealing with before kind of getting ahead of it" said CNN analyst Paul Cruickshank on Piers Morgan Live.

CNN: Why officials, media wait to declare bombing suspect

With the left withdrawing support, the government can rely on only 226 members in the 543-seat parliament, and needs 46 more to be absolutely sure of a majority.

BBC: India MPs hold vote of confidence