In essence, this is the question that fuels the balance of supply and demand in every market.

Look into every variation that motivates the potential customer (Doctors, nurses even secretaries and administrative staff), and continue asking subsequent questions until a final VALUE PROPOSITION and a final MESSAGE are developed. Question like:

Who will buy, at what price, with what options, in which locations, under what circumstances will they switch or remain loyal to the total experience.

If possible draft a Strategic Canvas and Brand Scorecard, to see where you would like to position your VALUE PROPOSITION

Do not hesitate to conduct focus groups and interviews (instead of polls or surveys) with your existing customers ans sales reps so you can draft out a road-map based on the actual customer lifetime value (CLV)

This will give you a clear time-line of activities for your first semester on the job. REMEMBER TO FOCUS ON YOUR SALES FORCE, only together will you maintain your strategy operational. . . Good Luck
References :
Id recommend two good Reference books, Strategy Maps and Blue Ocean Strategy helpful specially when reporting the strategy to your board of directors.