In most settings you generally call them by their first name. However, at school you always refer to them as "Dr. X." The academic setting is the only time I've seen the pharmacist refered to as Dr. I work in community and have done rotations in hospital/clinics and it is always their first name. Not all pharmacists have a PharmD as well.
I have been known to refer to the pharmacists that I work with as "Viceroy", "Professor", "Monsignor", and "Dictator". We don't take the title thing too seriously...😀
Honestly, at work, all of the bigwigs who I would talk to formally like that don't have PharmDs...
I would say anyone you're rotating with will usually have a pharmd and would want to be called that. Professors are always profs to me, regardless of PhD or PharmD. And work people...well, most shouldn't/don't care.