Heroin the heroine?

There’s no doubt that Trainspotting the film is about heroin. It shapes the narrative and the structure, and the film pretty well earns the alternative title of ‘A Junkie’s Progress’. De-personalising the issues, it goes like this: heroin is seductive and dangerous, and anti-social behaviour is part of the scene; there comes a time when the dangers and downsides can’t be avoided and it’s worth making an effort to stop using; if you are lucky enough to survive and avoid prison, conventional life, which is so scornfully rejected at the beginning of the film, looks a lot better than heroin.
But is Heroin treated as a character in the film? There are two musical moments when it sure looks like it. Bizet’s Carmen – Habanera plays while Renton makes his first attempts to stop using. That great seductress, Carmen, seems to mock and undermine his efforts: ‘You don’t love me, maybe, but I love you…’, his feet disappearing down the toilet bowl to the last chord. For ‘Carmen’ read ‘Heroin’. And the Big H seems to be a character as Lou Reed’s Perfect Day reassures Renton that oblivion is his perfect day. On the screen we see a young man in a dangerous overdose, but the music ignores that and follows his mood. As he is waking up and coming round there is the four-times repeated warning that he shall reap just what he sows. Heroin the heroine? Or the anti-heroine?