For people with reduced renal clearance, then taking ANYTHING including drugs becomes problematic for clearance.

For example, some drugs are cleared more slowly in the elderly.
Benzodiazepines are one example (Valium/Xanax etc).

When people have renal clearance problems drugs are eliminated more slowly. Some drugs are entirely cleared thru the kidneys and do not go thru liver metabolism. Examples are
Neurontin, Lyrica, Lisinopril.
Smaller doses are then needed.

Minerals like magnesium can build up in the blood when kidney damage is present.

But if the creatinine serum levels are in normal range, it doesn't matter if your take supplements. Kidneys do not metabolize anything. They eliminate substances, that are metabolized by the liver.

I see people taking up to 20 sophisicated drugs a day! Major polypharmacy. Do those same doctors consider that a risk to the kidneys? Nope.

There are drugs that DAMAGE the kidneys:
http://kidneyinthenews.wordpress.com...vil-nuprinetc/
Do doctors stop prescribing them? NOPE.
Drugs used in heart surgery, and some MRI dyes have damaged kidneys.

Vitamins and minerals in kidney disease:
http://www.kidney.org/atoz/atozItem.cfm?id=117

Massive use of acidic supplements like Vit C will change the pH of the urine and
crystalize out some substances...like uric acid (which is excreted daily) and oxalate.
This may lead to kidney stones. People prone to calcium or uric acid stones are often
given an alkaline agent called BiCitra to keep that from happening.
People who make too much uric acid due to metabolic issues, may develop damaged
kidneys as a result (with no extra Vit C necessary).