Floyd Mayweather received two intravenous vitamin injections before his May fight against Manny Pacquiao, contrary to World Anti-Doping Agency guidelines, SB Nation reports.

Floyd Mayweather received an intravenous vitamin injection before his May fight against Manny Pacquiao, contrary to World Anti-Doping Agency guidelines, SB Nation’s Thomas Hauser reports. Mayweather received an retroactive exemption for the IV after the fight

Employees of the U.S. Anti-Doping Agency who arrived to give Mayweather a random drug test after the fight’s weigh-in “found evidence of an IV being administered” to the boxer. Nevada State Athletic Commission executive director Bob Bennett told SB Nation that USADA did not clarify to the NSAC whether Mayweather was receiving an injection when the collection agents came to his home.

According to Mayweather’s medical team, the fighter was given two different vitamin mixes to treat dehydration. While the injections did not include any banned substances, IVs are still banned under WADA guidelines because they can be used to “dilute or mask the presence of another substance,” Hauser explains.

Nearly three weeks after the fight, USADA granted Mayweather a retroactive therapeutic use exemption to receive IV injections. USADA told the NSAC that Mayweather had not applied for the TUE until 18 days after the fight against Pacquiao, 19 days after his test, according to Hauser's report.

Drug testing guidelines were a major hurdle to arranging the much-anticipated Mayweather-Pacquiao fight. The two fighters’ camps spent the better part of a decade negotiating the terms of a potential bout, with drug testing as a main sticking point. Sports Illustrated’s Greg Bishop detailed the terms of the testing program in an April story.

Mayweather, 38, went on to win the fight against Pacquiao by unanimous decision.

The full SB Nation piece raises larger questions about drug testing in boxing.

- Dan Gartland