I don't think it looks as bad as a failing grade, but you should be ready to explain the reason behind the W during an interview or maybe in supplemental essay.
One or 2 "W"s is not a big deal. Just don't make it a habit. And it's definitely better than not passing because that will pull down your GPA considerably (whereas Ws are not calculated into your GPA) and pharmacy schools only accept a C grade or higher.
One or a couple w won't kill you. I had one on my transcript and 3 classes with pass grades. They didn't even ask me about it and the classes. Just be sure of everything else