For the American composer Missy Mazzoli, the opioid crisis isn’t a distant news event. It’s family history.

One cousin died, alone, of an OxyContin overdose in 2008. Three years later, another cousin died of an overdose of heroin, a drug she started using after getting hooked on prescription painkillers.

“That destroyed my aunt and uncle,” Mazzoli recalled in an interview, “and it destroyed my father, really — the pain of losing someone like that.”

Then, in 2016, a friend Mazzoli and Royce Vavrek, the librettist, had in common died of an overdose. “We didn’t know anyone who hadn’t been touched by this crisis,” Mazzoli said, adding that their growing appreciation of the issue’s scale led them to a thought: “There’s something operatic here.”

Now, Mazzoli and Vavrek have revealed the result of that tragic brain wave: “The Galloping Cure,” a fantastical, furious and, at times, funny opera, which premiered on Sunday at the Edinburgh International Festival.

After two more performances in Edinburgh this week, “The Galloping Cure” will transfer to the Norrlandsoperan in Sweden. The piece’s U.S. premiere is planned for fall 2027 at San Francisco Opera.

“The Galloping Cure” starts with the residents of a dilapidated industrial town complaining about chronic pain to a doctor (Daniela Mack), who struggles to help. The townsfolk’s situation changes only when a charming stranger, Lucky Mack (Justin Austin), arrives with a carousel that provides instant relief to anyone who rides its dazzling white horses.

Soon, the residents are renting hobbyhorses from Lucky Mack to get a fix at home and will stop at nothing to spin around on the carousel again — even if it means letting him remove their eyes, hair, kneecaps and tongues.

The allegory of “The Galloping Cure” carries extra significance given how many opera companies in Europe and the United States once benefited from the largess of the Sackler family, whose Purdue Pharma company made and marketed OxyContin, the highly profitable painkiller widely associated with the opioid crisis.

The Metropolitan Opera in New York and the Royal Opera House in London accepted Sackler-linked donations. So did Scottish Opera, which is a production partner for “The Galloping Cure” in Edinburgh and used Sackler money to help pay for the refurbishment of its Glasgow theater, where “The Galloping Cure” team rehearsed. (Scottish Opera said in an email that its understanding of the Sackler family’s “connection to the opioid crisis” had changed since it accepted the donation and that its sympathies were with those affected.)

The piece’s portrait of addiction is likely to resonate more broadly in Scotland. Although the country never experienced a prescription opioid crisis on the scale of the United States, it has a longstanding problem with heroin and other drugs. In 2024, more than 1,000 people died from drug misuse there, according to government data.

Mazzoli and Vavrek said in recent interviews that when they started work on the opera, they decided it wouldn’t be a “dour moralistic” production or refer directly to the crisis. Mazzoli said she didn’t want to give the Sacklers “any more space” by alluding to them in any way.

“Art is a place to honor our dead, to ask big questions and tell meaningful stories about the way America and the world are,” Mazzoli said. “I didn’t want to sully it with that.”

The composer and librettist commissioned Karen Russell, the American novelist, to conjure an allegory as the basis for the opera, and Russell came up with the carousel idea. Then they joined up with the director Tom Morris, known for “War Horse,” and created a scene-by-scene plan for a rapid-fire piece. Morris said he wanted it to be reminiscent of “Trainspotting” — the darkly comic British movie about heroin addicts — and “Sweeney Todd,” the gruesome tale of a murderous barber.

The music in Mazzoli’s score was inspired by the jingles of slot machines (another addictive amusement) and the sounds of carousels that she heard in Paris and Coney Island. It features passages in which the orchestra plays woozily to mimic the dizziness of a funfair ride or swells to evoke the euphoria of a drug high.

Yet when a character dies, the orchestra goes silent, leaving voices to echo around the theater. Mazzoli said she was thinking about her cousins who overdosed alone when she wrote that part. “It makes me tear up to think about it,” she said.

Morris, the director, said his main challenge was to ensure that the audience would find the carousel seductive and want to join the townspeople in taking a spin, rather than judging their choices. He and Rebecca Ringst, the set designer, decided against an actual carousel and instead went for several life-size white horses that soar skyward as the rider is bathed in neon light.

The show’s lavish design and sumptuous music might lead some audience members to hope for a happy ending. Mazzoli said some might be expecting the doctor to vanquish Lucky Mack and his evil carousel.

But she said that wouldn’t ring true: “That is not the world that we live in.” The opioid crisis is still happening, she added — and yet many people also benefit from painkillers. In the opera, she said, her characters need to work out how “to live with the devil.”