An independent panel to the US Food and Drug Administration (FDA) has said that Merck & Co's drug to reverse the effects of muscle relaxants used in surgery is safe and quite effective to warrant approval.

The chemical name of the drug is sugammadex. FDA has repeatedly rejected it over concerns related to potentially dangerous allergic reactions, even though the drug has the approval in over 75 countries.

The drug was acquired by the company when it purchased the US drugmaker Schering Plough, which created the drug sugammadex in 2009.

On Friday, Merck shares fell 1%, following a separate statement given by the company on Thursday, in which the company said that it had got a civil investigation demand from a US Attorney's Office in Pennsylvania regarding the pricing of its asthma medicine, Dulera.

During a meeting on Friday, independent advisers to the FDA said that they were content with the potential hypersensitivity and cardiac risk linked to the drug when it was used in a monitored setting.

Panelists highlighted the fact that similar risks were present in existing agents.

Most of the voters are in favor of additional researched for the evaluation of risks in vulnerable populations like the elderly and obese, pediatric and pregnant patients.

The sale of injectable drug Sugammadex is done in over 50 countries. As of April 22, more than 12 million doses of the drug have been sold since it first received approval in 2008 in Europe.

On Wednesday, FDA staff had noted that hypersensitivity linked to the drug appeared to go up with higher doses, but not with frequent exposure.