Feline Idiopathic Cyctitis - 8 months long, need serious help.

My cat Cleo has been dealing with FIC for 8 months now.  It all began when my other cat Athena was dying from chronic kidney failure and then had to be put down.  Athena was her life long baby and clearly she is still having a hard time without her.  Cleo was hospitalized twice for FIC in the first 2 weeks after Athena passed away.  Because Cleo took Athena as her baby many years back, I thought it would be a good idea to get her another baby so I got her a kitten (worst idea ever).  Other than the high volume of stress dealing with a kitten that came from a shelter with giardia, I tried integrating the kitten with Cleo and it became apparent that Cleo was not happy with her around.  The kitten of course was very kitten like and wanted to play yet Cleo did not.  Over time I tried many things to integrate them however Cleo's constant unhappiness was very evident so I had to re-home the kitten.  Cleo went through FIC AGAIN when I gave the kitten away for the same reason as before....being alone by herself without Athena.  My vet and I are trying everything and anything in hopes of not having to medicating her for depression/anxiety.  She already deals with kidney and bladder problems from FIC so adding any antidepressants would just add to her existing health.  The only problem is.....nothing else is working.  As soon as she has a good day and I think that things are moving in the right direction, she takes 2 steps back.   Back comes the anxiety, lack of drinking, lack of urine output, lack of eating along with a big increase in meowing.  I have been using feliway since February, have tried new toys and switching them out regularly, I've tried bringing her outside on a leash as often as the weather permits, catnip, honeysuckle and more things that I just don't have the time to type out.  I asked my vet about the idea of getting an older subdued cat as a companion for Cleo.  Obviously I made a big mistake when I got the kitten so I want to make sure anymore decisions I make for Cleo are 100% the right ones.  My vet mentioned that some cats just don't want other cats in their home no matter if it's a kitten or an older cat and she feels like this would be the situation with Cleo.  I can't help but feel if I took the time to find the absolute perfect match for Cleo, that it could be possible that it would work out.  My hesitation to try this out is having to put another shelter cat through coming to my home because I worry if there would be a big chance that I would have to re-home it for the same reason.  I guess since I made such a bad decision before, i want to try and make the best one for her now.  My vet did mention that getting a dog would be a good idea since Cleo grew up with a small dog for 4 years.  This unfortunately is not an option for where I live. 

Please I would love your suggestions about either getting another cat or anything else I can try to ease her anxiety and depression permanently.  It just breaks my heart into a million little pieces to see her suffer like this and I am desperate to try anything to help make her healthy and happy.  She is my 9 year old princess that I love and adore.

Thank you very much.

Have you had a urinalysis done recently? Crystals can pass inconsistently. There one day and not the next. What type of kidney problems?

If she has crystals or stones treat those first. Monitor urine ph levels very carefully. If feeding dry food add water to the food.

My cat had an infection to start with, a few months later he developed crystals. It took a year to diagnose as they passed inconsistently. Turned into idiopathic cystitis as he strained to urinate even without crystals present.

The amitriptyline at 2.5 mg per day really helps relieve his symptoms. He no longer strains. I do monitor his urine ph to avoid getting crystals again. I try to keep him on a consistent food as changing foods will make his urinary issues worse.