A stagehand working for a gay pornography company has sued his employers in San Francisco Superior Court, alleging he was forced to inject performers with a controlled drug to prolong their erections.

According to the lawsuit, which was filed Friday, Ronald Baker of San Francisco claims he suffered emotional distress and anxiety-induced health problems when he accidentally pierced his finger in January after injecting a performer in the penis with TriMix, a prescription medication used to treat erectile dysfunction.

When he contacted his employer, Adult Entertainment Broadcast Network based in North Carolina, over concerns he may have contracted HIV, his bosses told him they did not know what to do, according to the lawsuit. When Baker discovered the models did not have prescriptions for TriMix, he refused to administer further injections and violate state law. His paychecks and health benefits were then cut off, said Elisa Stewart, his attorney.

Baker is suing for wrongful termination, emotional distress and violations of labor and professional business codes.

"They are injecting a controlled substance into all these models without checking with a doctor if it's OK for that person to have that prescription medication, and they are using people on the set to give the shots," Stewart said. "You have to be a nurse in the state of California to give an injection."

Because TriMix can help maintain an erection for several hours, she said, pornographers consider it a way to keep costs down and cameras rolling.

Calls to Adult Entertainment Broadcast Network were not immediately returned Saturday.

Meredith May is a San Francisco Chronicle staff writer. E-mail: mmay@sfchronicle.com