‘Hellblazed’ pointed us to the official DC Comics/Vertigo website, which now has all the details on the two versions of the Constantine comic book adaptation:
January 5, the comic book adaption of the movie staring Keanu Reeves. DC/Vertigo gave two editions, the adaption and the Hellblazer collection that has the first issue and the begining of Dangerous Habits which are both ploted in the film.
You can view the info at the link above.
Source: Hellblazed