The obvious is to avoid these people, and that's the accepted sort of advice. But sometimes you realise you're dealing with one and you're in a situation you didn't expect.
Is it possible to simply take advantage of their innate needs, rather than fall victim to them? I don't think doing so makes you a narcissist, it just makes you smarter than them.
Personally, I've been in the situation once and I wish I had just wrecked him. He thought so little of me, and I could have walked him down a path and pulled out when he needed me hurting him greatly. I instead pulled out early in that particular project.
It doesn't get talked about much. It's like they have a mythical status as a danger, when it could be a boon, maybe.