Chlorambucil Side Effects

[basilisk14]

Hi all. My kitty Kiwi was just recently diagnosed with small cell intestinal lymphoma. It didn't come as a huge shock as she was diagnosed with IBD several years ago. Anyways, the oncologist started her on chlorambucil 1mg daily (since changed to every other day) as the cancer was caught very early. She decided against prednisolone because Kiwi is also diabetic (2u PZI bid). However, Kiwi has become a bit sluggish (sleeping a bit more than usual) and her appetite has gone down a bit. More than enough to give her insulin, but not her usual self. I also did begin giving her ondansetron and mirtazipine. The vet also suggested to change the timing of the chemo. I guess my question is has anyone dealt with just the chlorambucil and is nausea/lethargy a common side effect and if so, did it subside when your kitty adjusted (from what I know pred would almost negate those effects)? Thanks!

 

[Larry and Kitties]

I would talk to your vet/oncologist to go to a higher dose of chlorambucil every two weeks. Years a go my diabetic Mario has SSIL and was originally treated w/chlorambucil M-W-F per the original oncologist Mario had. He later retired and the new one went to the larger dose every two weeks. That made a difference since before he was lethargic/poor appetite the day following the dose. Every two week dosing made a big difference. He still was off that day after the dose but that was only one day every two weeks.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3092124/

 

[basilisk14]

I would talk to your vet/oncologist to go to a higher dose of chlorambucil every two weeks. Years a go my diabetic Mario has SSIL and was originally treated w/chlorambucil M-W-F per the original oncologist Mario had. He later retired and the new one went to the larger dose every two weeks. That made a difference since before he was lethargic/poor appetite the day following the dose. Every two week dosing made a big difference. He still was off that day after the dose but that was only one day every two weeks.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3092124/

Thanks! I have read about that as well. I think that's why she changed Kiwi to every other day as well. She wanted to monitor her for 10 days on every other day before we discuss if we need to change again. I just didn't know if this was common. I just hate playing the dosing game (I know it can be a necessary evil) as she has been through so much!

 

[Wendy&Neko]

Sorry to be late to add to this, but I agree with Larry. The every two week protocol is much easier on cats. I've had three cats in a row with SCL (sigh!) and on chlorambucil. The two that started out with the every other day protocol (including diabetic Neko), did much better when I switched to the every two week protocol. It gave them a break from side effects, and is actually a lower dose (less toxic) with similar remission rates. Current SCL kitty has been in remission for 5.5 years after being on only the every two week protocol, and we've stopped the chlorambucil.

Side note, the latest couple issues of the vet oncology textbook mention the every other week dosing as the preferred method.

Instead of prednisolone, ask your vet about budesonide. For many cats, budesonide does not impact blood sugars. It did not for Neko, who could not handle pred due to her heart condition. Budesonide did reduce her GI inflammation and since she was well regulated, I could tell it did not impact her blood sugars.

It is also important to make sure your kitty is getting the right dose of ondansetron. As per the paper in this post: (2016) ISFM Consensus Guidelines: Diagnosis & Management of Feline Chronic Kidney Disease and the table on top of page 253, dosing is 0.5 to 1.0 mg/kg of cat, given orally 3-4 times a day. Some vets underdose this drug or use the injectible dosing, which is less. The drug doesn't last long in the cat, so frequency is also important.