Burning Addiction by B.L. Maxwell

Brennan Clayton lived a life of privilege and comfort, until experimenting with drugs in college led to him quitting school to live the life of an addict. His days are spent doing odd jobs for cash to pay for his habit. One night, he overdoses and nearly dies.
Doctor Lucas Martel works nightshift in the emergency room at Eureka Hospital. He’s reclusive and brilliant at his job, and he’s all too aware that not everything in Eureka is as it seems. He’s also a vampire, one who chooses to blend in with humans rather than feed on them.
Something strange is happening to the homeless and addicts on the streets of Eureka; many have gone missing or ended up dead, and others have overdosed on drugs so strong, no human cure can counteract them. Not normally concerned with human tragedies, the vampires can’t stand back and let this play out, or they risk exposing their world to the humans.
Brennan must face his demons, and Lucas will discover many things about himself, and what he believes to be true: a seedy underground of rogue vampires and drugs that must be stopped, at any cost.