Hi, just want to pass on my recent experience.
Briefly, I have been on Sutent now for 2 1/2 years, with minimal growth of tumors in lungs and abdomen, and a regrowth in the bed of my removed kidney completely resolved. One of the side effects for me was some hypertension. GP and oncologist agreed it would be best treated with a calcium channel blocker, Cadizem CD (to avoid stressing the remaining kidney). Over seven months the Cardizem seemed to have no effect on my blood pressure, though the dose was continually increased. But all the side-effects of my 37.5 mg Sutent were getting worse by the month. Foot and hand syndrome set in, nausea on the rise, mental fatigue, bleeding gums, diarrhoea etc. I was not travelling well, and barely surfacing in time to begin the next cycle. Finally the oncologist discovered that Cardizem had not been a good idea. https://online.epocrates.com/u/104475/Cardizem/Drug+Interactions explains why! The Cardizem was slowing my liver metabolism, so the Sutent was building up. (Hopefully the increased concentration did some good -- it would be nice to get something in return.) There are other sites, perhaps now out of date, that suggest Cardizem is OK to use in combination with Sutent, or simply advising caution. I'd advise a lot of caution.
I'm now on Micardis for the hypertension, and just cannot believe the huge improvement in my quality of life.