I have a patient that i would like to place on chantix, is the egfr important? if so, what range is ok? and what else should i check? thank you

Simple approach: Go: https://www.google.com/search?q=Chantix+eGFR & http://labeling.pfizer.com/ShowLabeling.aspx?id=557 & search for "Renal" as most any physician would understand. This way you are relying on clinical trial data. Though this only reflects the average response within the selected sample group, this is based on some degree of scientific methodology.