I never heard about this.
But as abbreviation I found this: http://en.wikipedia.org/wiki/N-Methyl-2-pyrrolidone
Or maybe:
Nurofen Migraine Pain tablet.
NMP can be a lot of thing. A slang name, abbreviation or anything.
Ingestion:
Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious
person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention if symptoms appear.