KD. Katie. Zombie.

A common street name for a variety of drugs, KD has taken on a frightening form on the city's east side.

Users writhing on the ground, wide-eyed and struggling to breathe. Standing but moving in slow motion. Sweating. Convulsing.

Indianapolis firefighter Scott Lebherz told IndyStar this variation of KD can take many forms — marijuana, spice, tobacco, even banana leaves — but shares a common trait: all laced with a heavy-duty household bug spray.

It’s cheap — you can buy a bag for about $20, Lebherz said — and it can give users a 45-minute, zombie-like high that leaves them nearly catatonic.

“You look at what it does to a bug,” he said, “and then you got to think what it’s doing to your brain, and your body and everything else.”

The practice of mixing drugs with other chemicals is not new to Indianapolis. Worrisome still is the problem it presents for medics and other rescue personnel who are faced with giving critical aid to people who have smoked or otherwise ingested some uncertain substance.

The uncertain substance continually changes.

Firefighters can’t be surprised:But I was shocked by people smoking roach spray.

More than a game:How IHSAA basketball tournament run lifts entire small Indiana town

In January personnel from Indianapolis Emergency Medical Services, the Indianapolis Fire Department and the Indianapolis Metropolitan Police Department responded to dozens of overdoses in or around Downtown’s Wheeler Mission. At least 17 guests were believed to have overdosed on "Katie" — another mix of spice and an unknown chemical or drug.

Most of the men were able to bounce back, but at least one was taken to the hospital and placed on a ventilator that week, according to mission leadership.

Indianapolis police said a subsequent investigation led them to several drug houses connected to the distribution of spice mixed with an unknown chemical. Officers made six arrests in connection with the overdoses and confiscated nearly 10 pounds of synthetic marijuana and five handguns.

"You’re looking at people who will mix (a chemical) with a drug as a way to try to make more profit," said Daniel Rusyniak, medical director of the Indiana Poison Center. "Cutting your drug with ingredients has been a longtime thing that drug dealers have done to increase profits."

Last year, a Tennessee man admitted to smoking a mix of methamphetamine and bug spray called "wasp" before ransacking a family's home and trying to cut himself at the family's dinner table in front of a woman and four children, NBC26 reported.

In Monroe County, Mississippi, authorities last year observed a trend of residents crystallizing wasp spray and injecting it intravenously, a fix called "hotshots," NewsMS reported.

“Oftentimes, when they mix a substance, they're just trying to enhance the predicted high,” said Dan O’Donnell, medical director for IFD and IEMS.

O'Donnell said these ever-changing combinations present an ongoing challenge for first responders and medical professionals.

A person’s reaction to a mixed drug like KD depends on the concentration of the chemical, the ingredients used to produce the base substance and their own physiological response to that substance, he said, making it especially difficult for responders to know exactly what they are treating.

"Someone can go from extremely combative to suddenly unconscious, not breathing and potentially in cardiac arrest," O’Donnell said. "... We try to stay on top of it as much as we can through education and training and situational awareness about just what drugs are in the city, but as soon as we kind of catch up to one, they seem to introduce a new substance out there."

The active ingredients in household bug sprays, pyrethroids, are generally considered to be safe in small exposures, Rusyniak said. Exposure to high concentrations could induce respiratory distress and neuroexcitations, leading to sweating, muscle spasms or seizure, and the risk of falling into a coma.

"It’s why we use it on bugs," he said, "because it overstimulates the bug, they have the equivalent of seizures and die."

Despite likely knowing the dangers of ingesting bug spray, people who are most likely to do so are those who already are struggling with deep addiction and abuse issues, Rusyniak said.

"It’s a different decision making process," he said. "There’s a difference between, 'What’s bad for me,' which requires you to think forward … versus, 'I need to get high now.'”

For their part, police can only play a limited role.

Officers can't arrest someone for possessing a household substance like bug spray, IMPD Sgt. Chris Wilburn said.

"If someone sprays a legal substance on something that is harmful to their health," Wilburn said, "that is not ... in their scope to diagnose this person as being a criminal.”

The risks of the unknown are not just immediate, either, for users.

“If they go unconscious and not breathing, they could have problems just from that event,” O’Donnell said, “let alone what are the downstream effects of these drugs, three to five, six, seven, 10 years from now.”

Call IndyStar reporter Holly Hays at (317) 444-6156. Follow her on Twitter: @hollyvhays.

Call IndyStar photojournalist Robert Scheer at (317) 444-6464. Follow him on Twitter: @bobscheer.