SALT LAKE CITY — A Utah man who alleges in a new lawsuit that a McDonald’s employee spiked his drink with a heroin substitute said he had just seated his three young boys on the couch with their happy meals when he took a drink from his Diet Coke while he read work emails on his computer.

Trevor Walker said he suddenly lost feeling in his arms and legs and his vision became distorted. He thought he was having a severe anxiety attack. Before he blacked out and collapsed, he sent two text messages to his wife who was working in the in-home hair styling salon, according to a lawsuit filed Monday in Utah state court.

“I am having sensations in my arms and everything is moving slowly. I’m feeling scared,” he texted. “I don’t know what to do. I’m so scared I’m trying to be calm. I need you.”

Walker, 33, survived the August 2016 incident after being taken to the emergency room, but now he’s suing McDonald’s and Coca-Cola after settlement talks with McDonald’s broke off, he said Wednesday in an interview.

“It was kind like of like getting punched in the face without knowing it’s on the way,” Walker said, a software engineer. “I was with my kids: that was the part that made it especially scary.”

McDonald’s spokesman Khim Aday said the company doesn’t comment on pending litigation.

Coca-Cola spokesman Ben Sheidler said in a statement: “The safety and integrity of our products are our top priority. We’re working with our customer on this matter to understand the facts.”

Police investigated the incident at the McDonald’s in the Salt Lake City suburb of Riverton but never made arrests after all the employees interviewed denied wrongdoing, said Detective Jared Richardson of the Unified Police Department in Salt Lake City.

Richardson said surveillance video from the night of the incident in the drive-thru wasn’t available according to McDonald’s because that footage runs on a two-week loop and the request came in too late.

The lawsuit says the state crime lab determined the heroin replacement, called buprenorphine. It is a replacement for heroin or opioids that usually comes in a dissolvable film, Walker’s attorney explains in the lawsuit. A photo included in the filing shows a white filmy substance and speckles floating at the top of the Diet Coke.

Investigators could never determine how it got there, Richardson said.

The Salt Lake Tribune first reported the lawsuit.

In 2014 a Utah woman nearly died after unknowingly drinking iced tea mixed with chemicals at a Dickey’s Barbecue in a Salt Lake City suburb. Prosecutors declined to file criminal charges in the incident. The woman settled with the barbecue chain for an unknown amount of money.

Walker said at first he was relieved to find out the drug had been put in his drink because he was worried he was having some other kind of health condition. But he then was overwhelmed with bewilderment over why someone would spike his drink.

Richardson of Unified Police said investigators never had a suspect.

Walker said he had trouble sleeping and PTSD symptoms after the incident. He and his wife, Rachelle Walker, 31, said they still get anxiety eating out at restaurants.

He’s asking for unspecified damages and said he wants McDonald’s to take responsibility for what happened.

“I would like there to be some justice for what has taken place. I don’t want to see somebody else go through what we’ve gone through,” Walker said. “It could have been my son. If one of my sons had drank my drink, the outcome could have been worse.”