Cape Town - Wladimir Klitschko's promotion agency, K2, has filed a lawsuit against Kubrat Pulev relating to doping allegations.
"K2 is suing me for my words," Pulev said on Tuesday. "The case is... I have no right to speak on this topic, the doping."
The Bulgarian was knocked out in the fifth round when he challenged Klitschko for his IBF heavyweight title in Hamburg earlier this month.
Pulev, who had won his previous 20 fights, protested several times about being subjected to rigorous drug testing, saying Klitschko had not been tested at all before the bout.
He repeatedly called for his 38-year-old opponent to be tested but the Ukrainian refused.
"You can respect him, he's a world champion," said the 33-year-old Pulev, who became the IBF international champion in 2011 and European champion in 2012. "But nobody can force me to respect a man when I saw all his dirty tricks."
Pulev failed to attend a news conference before the fight after being informed that only three members of his camp could be present.
He also accused Klitschko in August of feigning injury to avoid fighting him in September. Klitschko postponed the fight, saying he had torn bicep muscles during training in Austria.
Klitschko, who also holds the WBO, IBO and WBA titles, has won 63 of his 66 professional fights. He knocked out Pulev with a fierce left hook on November 15.