Nurse Jackie, BBC Two

Medical dramas have a never-ending appeal to television viewers; but whereas British versions are more about the heartstrings than open-heart surgery, America prefers its programmes to be done with scalpel-sharp wit and incisive social commentary. So a warm welcome back to Nurse Jackie, a sassily written and joyously dark work set in a New York emergency room, for a second series.

The Showtime programme follows in a distinguished line of well-written and pacy ensemble American medical dramas and comedies, including St Elsewhere, ER and Scrubs, and the more recent addition of House (although I struggle to get past Hugh Laurie’s dreadful approximation of an American accent). The titular character at Nurse Jackie's centre - a dedicated and experienced practitioner who also happens to be a drug-addicted adulterer leading a double life - is played with great subtlety and nuance by Edie Falco (Carmela in The Sopranos).

The first series ended with Nurse Jackie, who had accidentally overdosed on the Vicodin she stole from work, collapsed on a hospital bathroom floor. Last night opened with her still flat on her back, but waking up not from a coma, or even in one of the dream sequences that creators Liz Brixius, Linda Wallem and Evan Dunsky use occasionally. In fact, she was spending a day at the beach with her husband, the sweet, uxorious bar owner Kevin (Dominic Fumusa) and their two daughters. Like much in Nurse Jackie (such as why she is leading a double life, with her colleagues mostly unaware that she is married with children), how she got from tiled floor to beach towel was left unexplained, a welcome departure from the exposition-heavy formula of inferior dramas.

Then we saw her back at work, where the nursing chief (a wonderfully humourless turn by Anna Deavere Smith) asked Jackie to inform nurses that the local health authority has noticed a suspicious spike in drug use at the hospital since the pharmacy was shut down (leaving Jackie’s lover and drug supplier Eddie out of a job). To save money, Eddie was replaced by a computer-controlled dispensing machine and - in a wonderfully neat trick by the writers - even as Jackie was, straightfaced, telling her co-workers how to use the machine correctly she managed to score yet more powerful narcotics from it.

But Jackie, for all her weaknesses, is a good person; in this episode she supported a diabetic colleague who was not managing his insulin properly and nearly collapsed at work and sweet-talked an insurance company employee into authorising an expensive operation not covered on a patient’s policy. America's crazy health-insurance system is exposed as the dark comedy it is, but politics are never allowed to take centre stage.

The opener was an efficiently written and brisk scene-setter, and foils to Nurse Jackie (and scene-stealers all) were back in tow, including Britain’s magnificent Eve Best as best friend and gifted surgeon Dr O’Hara, who dresses in high heels and tight skirts and speaks with dripping irony, nursing student Zoey (Merritt Wever), innocent but becoming sharper by the minute, and smug but vulnerable Dr Cooper (Peter Facinelli), hopelessly in love with Jackie.

The half-hour, as ever, just rushed by, but was full of acerbic put-downs by Jackie and nice little pointers to storylines that will unthread over the next 11 episodes, including Jackie's daughter’s apparent OCD, Dr Cooper’s dangerous knowledge of her private life and Eddie’s suicide attempt. Which one will undo her, I cannot guess, but I am suitably hooked.

• Watch Nurse Jackie on BBC iPlayer
• Find Nurse Jackie on Amazon
• Find House on Amazon

Watch the trailer for Nurse Jackie