Pharmacology Certification by NAPNES?

i recently applied to take the pharmacology certification test given by NAPNES (national association for practical nurse education and service).

has anyone taken the test? was it very difficult?

i bought a pharmacology review study guide from barnes and noble, but i'm not sure if i need to be studying at a "tougher", more complex level or if this guide will do. the guide covers all bases as far as i can tell, even general dosage calculations. however, it doesn't highlight some areas that i would imagine the NAPNES test would require: mechanism of action, drug classification, etc.

i have been a nurse for 7 years and feel fairly well-educated about pharmacology, but i just want to make sure i'm prepared to take this test!

any comments are much appreciated!