Self-described “sweary lady” Lisa McInerney was the voice of alternative Ireland before she abandoned her blog The Arse End of Ireland and joined the mainstream literary world. For several years, she’d documented the highs and lows of life on a Galway council estate with joyful cynicism. She then deleted the blog and drew on the material to create her first novel, The Glorious Heresies, which won last year’s Baileys women’s prize for fiction.

That novel moved between the heads of a young rebel, a prostitute and a grandmother-turned-murderer in energetic, casually inventive prose. It was the troubled adolescent, Ryan, who was the focus for writerly and readerly sympathy, and it’s his story that takes centre stage in The Blood Miracles, a novel related entirely from his point of view.

At the end of The Glorious Heresies, he’d returned from a spell in juvenile prison to a life of more serious crime, disappointing his girlfriend, Karine, but fulfilling the expectations of his ineffectually criminal father. The relationship with Karine was the only thing keeping him attached to life, yet he felt compelled to destroy it with repeated infidelity and drunkenness, and the novel ended with him standing on the banks of Cork’s river Lee, cajoled away from the brink by an elderly woman. The new book begins with Ryan recovering from a suicide attempt, embarrassed that he has tried to do away with himself with so tame a substance as paracetamol and that Karine as a nurse-in-training has taken responsibility for his recovery.

This is a moment when Ryan’s path forks. He could follow Karine’s advice and give up on crime, accepting penury and infantalisation by returning to school to do his exams. Or he could join his boss, Dan Kane, in importing a particularly pure form of ecstasy from a new source in Italy and transforming the life of the city. Apparently incapable of actively choosing anything, Ryan seems to sleepwalk his way into the drug deal. He loses Karine but falls straight into the arms of Natalie, a posh accountant with a penchant for the underworld, who turns out to be also having sex with Ryan’s boss.

The lack of options confronting Ryan is painful and it becomes clear almost everyone he meets is a user or an alcoholic

The resulting struggle makes for an addictive read: even more so than the previous novel, because of the intensity of the single plot line. We want Ryan to survive, ideally safely away from the criminal world but otherwise on the right side of it. The speed with which events progress makes it more a novel of plot than character, though Ryan does pause to address his dead Italian mother in monologues. The other characters are more sketchily drawn and the genre is more consistently picaresque than it was in the previous book, where it was offset by the gentle exploration of the love that surprised and then frequently overwhelmed Karine and Ryan.

It’s a temptation for writers to use the picaresque mode to create either a thriller or a social critique, but McInerney resists both. The hardships of working-class life are addressed. The lack of options facing Ryan is painful and it becomes clear that almost everyone he meets is a user or an alcoholic. But if we’re told that Cork, “like all cities, hates its natives”, then this is as much a love letter to a cruel but curiously buzzing place as a lament. And the drugs that fuel the city are seen as thrilling as well as damaging.

Phenomenological investigation of contemporary drug use … Lisa McInerney. Photograph: Alamy

Compellingly, McInenerny offers a kind of phenomenological investigation of contemporary drug use. We learn about the precise effects of “smoke, coke and yokes [ecstasy]: St Paddy’s modern trinity”. At a desperate moment, Ryan takes an ecstasy tablet. Blinking, “he feels his lashes lift from his skin. His throat relaxes. His pupils flood. The euphoria surges from the floor to his calves, to his thighs, to his groin, his belly, his shoulders.” In this state, he becomes more receptive to the dance music blaring around him. “Ryan chews the notes and forces them down, like they might moor him, like the music might stop him spinning back into the dark.”

What kind of redemption is possible within this? Ryan has his music; he surprises all those around him with occasional piano recitals, having been taught to play by his music-loving mother as a child. There is family love. Ryan’s father is grounded by his children, though he spends more time hitting them than helping them. Ryan longs for a baby to tie him to life, though he knows that he is in no state to look after one.

It is possible that redemption is unnecessary. The great strength of this book is its amorality. If you can survive in this world, and learn to live without always watching over your shoulder for danger, it’s not a bad place to be. Natalie is no worse when she uses her accounting skills in the service of unlawful than lawful enterprises. It’s hard to imagine who Ryan would be if he packed it all in and got the kind of badly paid manual job he’d be qualified for. By the end of the book we’ve half lost hope that Ryan will reform and return to Karine. We have also lost confidence that Karine’s way – the way of passing exams and paying taxes – is necessarily the best mode in which to live.

• Lara Feigel is the author of The Bitter Taste of Victory: Life, Love and Art in the Ruins of the Reich (Bloomsbury). The Blood Miracles is published by John Murray. To order a copy for £11.24 (RRP £14.99) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.