He says trauma from the violent attack left him in Swedish Hospital, unable to walk for days.
He says the incident began when he was given a drink laced with drugs at the home of an acquaintance.
He says after he was attacked inside the home, he stumbled, dazed, into Volunteer Park.
He says someone called 911 and the next thing he knew, he was in Swedish Hospital, being treated for a drug overdose.
He says he told his story to hospital staff immediately.
"Nobody else knew about it because of the shame," he said.
It was the shame and the guilt and the feeling that I'm not going to be believed. I kind of feel like that's what happened at the hospital."
Antonio says he expected someone to discuss his options, including reporting the crime to police.
He says staff expressed deep sympathy, but did not help him understand his potential next steps.
Eleven days after the attack, he called Seattle police himself from the hospital.
"When I talked to the police, they said (the hospital) should have performed a rape kit within the first five days," he said.
"In fact, not only did they not do that, they actually bathed me while I was in bed, so they essentially washed away any DNA evidence that would have been there after I told them I'd been assaulted."
A spokesperson for Swedish Hospital told KIRO 7 federal laws prevent them from giving any information about their patients.
Spokesperson Mary Beth Lowell did say Swedish Hospital staff are trained to recognize and react to victims of sex crimes.
"We take our patient care and safety very seriously at all of our facilities and follow specific and disciplined procedures when patients notify us of a sexual assault," Lowell said in a written statement.
"We are committed to always providing the best and most compassionate care for each and every patient."
Antonio said he did receive compassion from the staff, but he wonders if the reaction to his story would have been handled differently if he were a woman.
"Seattle police handled it in a great, sensitive way," he said. "I needed counseling and advice long before I called them."
The King County Sexual Assault Resource Center advises all adult rape victims that it is their responsibility to report their crime to police themselves, even if they're a patient in a hospital.
Antonio still hopes his story increases awareness that male rape is an under reported crime, because many victims are embarrassed to seek advice on their rights, and the resources available to them.
"There needs to be a safe environment for a man who's been sexually assaulted to be able to come forth and feel comfortable and know they're going to be validated and they're going to be helped," he said.