Merck & Co’s neuromuscular blockade antidote Bridion has won US approval for the reversal for general anaesthesia induced by the agents rocuronium or vecuronium, following a stream of knock-backs over safety concerns.

The drug provides a new treatment option “that may help patients recover sooner from medications used for intubation or ventilation during surgery,” said Sharon Hertz, director of the Division of Anesthesia, Analgesia and Addiction Products in the FDA’s Center for Drug Evaluation and Research, and “enables medical personnel to reverse the effects of neuromuscular blocking drugs and restore spontaneous breathing after surgery.”

The US Food and Drug Administration said the approval is based on Phase III trials involving 456 patients which showed that recovery time was faster overall for the Bridion (sugammadex) treatment groups compared to the comparator groups, with most participants recovering within five minutes of routine use of the drug.

On the safety side, there were concerns about the nature and frequency of anaphylaxis and hypersensitivity reactions reported in the clinical trials, so Bridion was further evaluated in a study which showed that, of 299 participants given the drug, one had an anaphylactic reaction. Clinicians should be aware of the possibility of a hypersensitivity reaction or anaphylaxis and should intervene as appropriate, the regulator said.

Also, cases of marked bradycardia, some of which have resulted in cardiac arrest, have been observed within minutes after the Bridion administration, so patients should be closely monitored for haemodynamic changes during and after reversal of neuromuscular blockade, and treatment with anticholinergic agents, such as atropine, should be administered if clinically significant bradycardia is observed.

The most common adverse reactions reported in clinical trials included vomiting, low blood pressure (hypotension), pain, headache and nausea. Doctors should also advise women using hormonal contraceptives that Bridion may temporarily reduce the contraceptive effect so they must use an alternate method of birth control for a period of time.

Bridion had been knocked back three times in the US as regulators stalled over its potential side effects, but was approved by regualtors in the EU back in 2008.