John Roach looks up at wife Rosemary from his bed in room 133 at the Hospital San Jose in Monterrey, Mexico. “Don’t say goodbye,” he pleads as doctors prepare to send the burly grandfather from Allentown, Pa., into unconsciousness. “It’s okay,” Rosemary says. “Pleasant dreams.”

Soon, deep in a coma, John descends into a frightening, topsy-turvy world. Scene: He’s in a strange house with paintings on the ceiling. Scene: He’s watching as his cat rushes into the path of an oncoming car. Scene: He’s a World War II soldier fighting on a blood-soaked battlefield. “It was weird and frightening,” John recalls of his voluntary, five-day ordeal in late May. “But I needed to do something.”

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Suffering from a debilitating neuromuscular disorder called reflex sympathetic dystrophy (RSD), John, 50, is one of about 100 chronic-pain patients resorting to a radical new treatment in search of relief—a medically induced coma using ketamine, a surgical anaesthetic and hallucinogen sold illegally as “Special K.” Advocates say ketamine comas can be a godsend for some. “We’re giving people in excruciating pain a normal life,” says Dr. Robert J. Schwartzman, neurology chairman at Philadelphia’s Drexel University College of Medicine; since coma therapy isn’t FDA-approved, he’s sent more than 60 patients to Germany and Mexico. But other experts say the treatment, which costs as much as $50,000 with travel, is too risky. “Vulnerable people are getting something expensive and potentially dangerous,” says Dr. Norman Harden of the Rehabilitation Institute of Chicago.

Some 200,000 people suffer from RSD, in which ordinary pain escalates to crippling levels. “Think of holding a blowtorch to your skin,” says John, whose entire left side was affected after he fell down rotted stairs and tore his rotator cuff in 2002. Because ketamine blocks pain receptors, Schwartzman says, very high doses can restart the nervous system, “like rebooting a computer.”

Brandy Sachs, 23, of Christianburg, Va., had spent seven years in a wheelchair after a finger injury and ankle sprain spiralled into all-over agony. “I was giving her pain meds in doses that would have killed a horse,” says her family doctor, Jeremy Freeman. Last fall, after undergoing a five-day coma in Germany, Brandy needed months of therapy to relearn how to walk, talk and eat. But now, she says, she’s pain-free and plans to start her master’s degree: “It’s a miracle.”

Not always. In October 2008, RSD patient and mother of three Laura Beckett, 47, of Magnolia, N.J., developed pneumonia while in a coma in Germany and was kept under for three weeks as doctors fought to save her. She woke up paralyzed from the neck down and now lives at a rehabilitation center. “It’s an understatement to say things went wrong,” says husband Karl, though he adds his wife’s pain was so unbearable they would likely choose the coma again. Says Schwartzman: “We’ve had tragic outcomes. But this is only attempted after every other treatment has been tried.”

John, a jovial retired phone-company worker, had tried surgery, physical therapy and heavy doses of pain medication, including OxyContin, codeine and fentanyl. When nothing worked, he thought of ending it all. “I couldn’t be touched,” he says. “I couldn’t hold my wife’s hand or sleep next to her. It wasn’t the life I wanted.”