I Am Being Treated For Low Magnesium I Was Taking

I am being treated for low magnesium I was taking tablets prescribed by my oncologist which have been inflaming my rectal area I stopped using the tablets and made arrangements for an IV drip to help me build up my levels at first I did not have a reaction from the drip as of yesterday I am having the same problem my mistake was I took magnesium tablet 250 mgs before having the last drip if there is a solution to my problem I would appreciate it very much, I am also being treat at MSKCC for cancer of the throat and lung and receive chemo every third week