If they are house cats, try giving them rainwater to drink instead of your flouridated and chlorinated tap water.
For everyone who questioned the water, our pets all get RO water. We never drink from the tap and neither do our pets.
We add water to Luke’s food to help him produce. We might have to start doing the same for Drake.
For everyone mentioning blockage: they ARE passing urine. They problem is that their urinary tract gets inflamed from the crystals and causes them to think they have to urinate when their bladders are really empty. The anti-spasmatics help, but I don’t want to have to pill them forever.