Swiss law on prescriptions is *weird*.
There are categories of medicines (Abgabekategorien) with a clear demarcation between requiring a prescription (A-B) and not (D-E). Notably category C is missing, because it was eliminated in 2019 (it used to be "can be sold in pharmacies only but without prescription" IIUC). Some of the stuff from C went to D, some of it to B.
That would be clear. However, "this medicine was once in C" is an exception to the requirement for prescriptions for medicines in B! (See https://www.fedlex.admin.ch/eli/cc/2018/588/de#art_45) Thus, we effectively still have C, but it's way more confusing.
This story was brought to you by a pharmacy wanting a prescription for KCl from me. (Which I'm really amused ended up in B, given that it has a similar safety profile to table salt afaik: you can overdose on it, it can have bad interactions with your other medications or diseases, it's kinda hard to overdose without really trying.)
(I was very surprised by the requirement and pharmacist was very surprised by my surprise, so I think they were unaware of this exception applying as opposed to not willing to apply it.)