1) What exactly is your GPA
2) Does this class fall as a prerequisite for your conditional acceptance
A "W" has no weight on your GPA as an "F" does. However, if you are currently failing the course, your withdrawal would not be a "W", it would be a "WF" which will bring down your GPA just as much as an "F" would. In this case, it is better to grind through the class with the possibility of getting anything higher than an F since a WF would essentially make no difference in bringing down your GPA.
If this has no hinderance (as in not a conditional prerequisite) for your acceptance into pharmacy school, then just withdraw. This may ratify any scholarship(s) you may be on if you drop below the required credit hours for the semester.