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1.
75 y.o. with a lot of drug for HTN, OA, and cholesterol. Which age-related decline in the following pharmacokinetic process is most likely to affect this treatment?
a. gastric absorption
b. hepatic glucorunidation
c. hepatic oxidative metabolism
d. protein binding in the serum
e. Renal tubular secretion
Phase1 is decreased in elderly so I thought C is the answer, but at the same time renal function is decreased so E might also be the answer.... What do you think?

2.
In FA pg.240, it is stated that prostate cancer is more likely to metastazie to brain than melanoma.
However I also learned that carcinoma of the prostate almost never results in metastatic brain disease. What's the right sentence?

3.
According to the explanation I attached, the clearance of both BUN and Cr are dercreased in CRF. However, if Cr is also lost in exrarenal sites(skin, GI), then shouldn't the serum BUN/Cr ratio increase? Obviously the ratio is <15 in intrinsic ACUTE renal failure, but I don't know if the explanation here is right in CRF.


(Thanks in advance!!)
 

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BUN/Cr<15

3. Urea is what is lost in extra renal sites, NOT creatinine. In renal azotemia, creatinine and BUN backs up into the blood, but urea is lost in extra renal sites, that's why BUN/Cr<15.
 
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