Reckitt said in a statement that it "acted lawfully at all times and expressly denies all allegations that it engaged in any wrongful conduct".
"It avoids the costs, uncertainty and distraction associated with continued investigations, litigation and the potential for an indictment".
Laxman Narasimhan, who was chief commercial officer at PepsiCo, will succeed Rakesh Kapoor at the helm of the pharmaceuticals, personal care and "home hygiene" (Air Wick, Lysol, Calgon, Woolite, Vanish) company on September 1.
Finsbury's Faeth Birch and Philip Walters rep RB.
The dissolvable film form of the drug was marketed as having a lower risk of being abused, but prosecutors say Indivior knew it could potentially be more risky.
In April, the U.S. Department of Justice indicted Indivior for its marketing practices of the opioid addiction treatment.
RB's outgoing boss Rakesh Kapoor launched a plan to split the group into two business units - one for health and one for hygiene and home products - under the same parent company.
Reckitt Benckiser shares rose 2.6% to 65.95 pounds at 0839 GMT on July 11.
Investors had feared the USA probes could hinder the transformation.
The US authorities criticised Indivior for having sought to take advantage of the opioid addiction crisis in the United States by exaggerating the safety of its drug Suboxone. Analysts at JPMorgan wrote in a note that the settlement "clarifies the legal environment for RB and should allow the new management to focus on the RB 2.0 transformation".
"The danger is that Narasimhan will be operating with one hand tied behind his back", he said.
"Opioid withdrawal is hard, painful, and sometimes unsafe; people struggling to overcome addiction face challenges that can often seem insurmountable", the Assistant Attorney General Jody Hunt for the Department of Justice's Civil Division said in a statement.
The settlement means the British consumer goods giant will have to raise the amount of money it has set aside to cover the cost of the investigations to $1.5 billion, from an earlier provision of $400 million, the company said on Thursday.
Separately, Indivior's shares shot up 37.7% to 61p after it raised full year profit and sales guidance thanks to a better than expected first half showing from Suboxone.
"Because the fine will be met through existing borrowing facilities and cash flow, Narasimhan will inherit a company in slightly straitened circumstances, particularly as the balance sheet had already been stretched by the 2017 acquisition of Mead Johnson for an eye-watering US$17bn".