Thank you for the reply.
When a cat is refusing to use the litter box for either urine or stool, but will still use it for the other. it tends to point more to a litter box aversion that started when perhaps she associated something unpleasant or painful with urination that occurred when she was in the box and now, she thinks that will happen again if she urinates in the box. It is not usually a matter of her not liking the type of box or type of litter, since she is still using it for stool, but more an anxiety about urination in the box.
You can sometimes train them back to the box, but since she has developed a new substrate preference (the floor in front of the box), you may want to offer her a few different choices. Assuming she is the only cat in the house, 2 litter boxes should be enough, but you may want to add a third in the area of the first two. It is best to offer her a "buffet of choices" to find her preference. Try different litters, different types of boxes (short sided, tall sided, etc) and different amount of litter in the boxes. Cat's are very texture specific so look at the places she is choosing to go. If it is a carpet, you may want to put a piece of scrap carpeting in a litter box for her and slowly add more litter as she starts to use it. Some cats, mine included, prefer to urinate in an empty litter pan with no litter at all. There is also a litter box additive called Cat Attract® which works very well. PRECIOUS CAT LITTERS LINK You may have already tried these, but they are suggestions that have helped many of my clients. Litter pan hygiene is key so regardless of the type of litter, you must scoop daily.
One other thing I would suggest is a product called Feliway®. LINK HERE Feliway is a synthetic pheromone that mimics the natural chemicals that a cat secretes. It creates a comforting, reassuring feeling that has a calming effect. It has been shown to decrease urine marking and spraying within 30 days with a 95% success rate. It is also calming to cats in stressful situations such as transport, hospitalization, veterinarian visits, boarding, new environments, pets or people. Feliway® is a product that can be sprayed or used as a room diffuser. It can be purchased through veterinarians and pet stores. I would definitely put a few of these around the house.
There are drugs that can be tried, but I would try the other things first. Even if you have to resort to drug therapy for a while, these are changes that should be incorporated at the same time. Anti-anxiety meds such as Prozac have been shown to effectively reduce urine spraying and the drug called gabapentin is very helpful if she is experiencing a urination anxiety.
This is a hard subject to cover adequately in a few paragraphs. I am including a link that may give you a few more ideas. Work with your veterinarian who should have experience with this also as this is a very common problem, but can be solved in many cases especially since she is still a young cat. I am also including links to a website that offer suggestions to provide environmental enrichment for indoor cats. This has become a very important subject as we have now identified that many cat behavior and medical disorders stem from the fact that they are confined indoors and forced to share territory with other cats, which is not how cats naturally choose to live. This "stress" can lead to physical and behavioral problems.
OSU Indoor Pet Initiative
I hope this is helpful. Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please reply so I can clarify for you.