I hope all of this works. I would try a a few things. I would do what you are doing with her food but if need be keep her in a room without food for 2 hours before and then feed her the wetfood with medication mixed in. If need be keep her in the room up to an hour afterwards (let it be her homebase room with litter box/scratcher/toys/water and if you can your bed.)
If it is real severe I would ask the vet for a mild sedative so she is calm and you can shove her medication she needs down her throat. We did that with our semi-feral when he had to be kept inside, medicated and get a daily saline IV.
If it is real severe I would ask the vet for a mild sedative so she is calm and you can shove her medication she needs down her throat. We did that with our semi-feral when he had to be kept inside, medicated and get a daily saline IV.