The Food and Drug Administration has just signed off on a new drug from Merck & Co. that would reverse the effects of muscle relaxants during surgery.

The FDA approved Bridion, which essentially is aimed at wiping the away the effects of deep paralysis from muscle relaxants like rocuronium and vecuronium, which are used at the start of surgery to help insert a breathing tube, according to a Reuters report.

FDA did warn that despite its approval, there is a possibility of a reaction or anaphylaxis, and clinicians should be prepared for this.

Another concern is that it can cause abnormally slow heart action, which can, in a worst case scenario, result in cardiac arrest within minutes of receiving the drug. As a result, patients getting it will need to be monitored by clinicians very closely, and they should be ready to step in quickly.

Still, it could be a boon to patients undergoing surgery who want to recover more quickly from its effects.

It could be a huge new product for Merck, pulling in up to $557 million every year by 2020, according to the report.

It’s not been an easy path to approval. Merck ended up with the drug after buying Schering Plough in 2009, which had itself purchased Organon BioSciences, the original developer of the drug, two years prior. The FDA had rejected it back in 2008 over concerns about allergic reactions and bleeding. The agency was going to look at it in 2013, but then said it needed to review the application.

Bridion is the trade name for the drug, and sugammadex is the generic name. It is an agent for reversal of neuromuscular blockade caused by general anaesthesia.

Sugammadex was approved for uses in the European Union back in 2008.