Renata doesn't have a long time, my vet and I have her on long term gent and dex sub-q every 2nd day. She has the dypsnea, lung sounds and lymphoma (2 masses), she is losing weight steadily and I am trying to keep her more comfortable. We went to the ratguide last night (my friend taught me how to do dosage conversions last night...woohoo) and we found that she was on a very very low dose and I found it wasn't working very well anymore. I am watching her carefully for any signs of disinterest in her life or discomfort. Poor girl. The dex shots have really improved her quality of life but they aren't working as well anymore.
Cado and I were on some of the same drugs, steroids being one. They have a cumulative effect in humans and I assume so in rats since precautions are the same. However, after checking with your Vet and confirming you're on a low dose, you're probably going to get an increase.
Steroids cause rats to drink, but people to eat. Knowing drugs kick in faster for rats, I switched Cado to baby formula. Since I have no life, it was easy to make sure he drank enough formula each day when he started passing on regular food. I kept regular treats handy ( ice cream was involved ), but he found baby food off the tip of my finger ( would NOT eat it any other way - such a silly boy

) or hand fed formula his mainstay.
Cado then turned his nose up to the normal med preparation, but would take anything from my finger. With Vet approval, I found cutting up pills (very inaccurate) and mixing them with baby food was less stressful than injections and not such a big deal given his quality of life vs time left. He was a happy little guy to the last.
I'm sure he's telling stories how he wrapped me around his paws.

Every word true.
Best Wishes