I've been on it for 16 months. Some tips: First, it has lots of side effects. Some are no big deal, some are mildly annoying, a few require watching so they do not produce anything dangerous. All of these concerns are mild compared with the concern that the Sutent actually work.
Second, of the more serious side effects - raising blood pressure to high levels is very common. This can be controlled with anti hypertension meds. Suggest consulting a cardiologist and maybe a nephrologist if you experience this. The blood pressure quickly goes back to normal during breaks in the Sutent cycle. It took me a few months to find the combo of blood pressure meds that keep mine ok through the cycle.
In my case (and I think commonly) the Sutent pretty much shut down my thyroid. This is no big deal, you just take thyroid supplement hormone pills each day. They fix teh problem and you do not feel anything. But import to watch your TSH (thyroid test) closely.
You should do a heart echo every six months approx. In some people the SUtent causes heart damage or changes. The echo rules out anything.
Regardly the mere annoying, in my case the worst are gastro issues, cramps, pains, gas, and the runs. These can be partly controlled with over the counter things. SOme people find probiotic pills (the "good" bacteria - from health food stores) helps.
Other side effects are fatiugue, muscle weakness, changes in taste in mouth, hair turning white(r), dry skin, watery eyes sometimes, days with low appetite. Other people report some other side effects.
Live for the BREAKS in the Sutent regime! Party time!
I recently switched from the 4-week-on-two-week-off regime to the 2-week-on-one-week-off regime and the side effects are MUCH better.