I just know the one time I tried Poppers, the bottle spilled. Never, ever attempted use again. The 'high' was short-lived anyhow. If you watch porn-stars on video, they're taking really LONG hits of this stuff, not short sniffs. And several hits at that.
I've always heard of damage to the brain from overuse of Amyl Nitrate, let's be honest, what drug doesn't harm you in some fashion or another. If you choose to try this, see how it affects you, and your body, then make the decision to continue. As for me, once was enough to make my decision.