Dear Rosa,

Decline in eGFR is inversely proportional to the rise in creatinine
and is affected by multiple factors apart from kidney failure: a high
protein intake, increase in protein breakdown caused by strenuous
exercise, or dehydration causing a relatively higher concentration of
creatinine. Norvasc / amlodipine, a dihydropyridine calcium channel
blocker, is not known to impair the kidney function. Common
medications that may affect the kidney function include ACEI / ARB,
NSAID painkillers, and diuretics. Are you taking Chinese herbal
medicine or any herbs or supplements that contain impurities? If
extrinsic factors are excluded, then one should focus on the kidney
itself. The differential diagnoses can be classified into three main
groups: "pre-renal" such as narrowing or blockage of the kidney blood
vessels; "intrarenal" such as inflammation of the kidney tissue due to
infection or autoimmune disease or congenital abnormalities; and
"post-renal" such as kidney stones or ureteric stones. One should
repeat the kidney function to monitor the progress, check urine
protein, blood glucose. For more advanced investigations, one would
also consider screening for autoimmune bodies (Lupus, other autoimmune
disease), imagings (Ultrasound, CT Urogram or MRI kidney), and finally
a kidney biopsy if deemed necessary. Coffee should not have a drastic
effect on the kidney apart from mild diuresis. If the heart has
anything to to do with the kidneys, then one would first consider
congestive heart failure leading to low blood supply to the kidneys
causing a rise in eGFR. Very rarely, chronic atrial fibrillation
patients might have a large atrial thrombus, which gets dislodged and
acutely occludes the kidney blood vessels. I have only encountered one
patient who had kidney artery embolism from atrial fibrillation,
throughout my whole medical career.

Sincerely,
Dr. Jason Ko