00:01
Let's do some questions. The first question. A 30 year old
male executive presents to the ER in kidney failure.
00:09
He is on an unknown over-the-counter
anti-inflammatory medication.
00:13
He has ingested cocaine on an intermittent for the past 5 years.
He is obtunded, edematous, and oliguric.
00:20
His renal function is falling with significant hematuria and
casts in the urine. Which of the following is true?
A, he was probably taking celecoxib, which can cause
renal failure and may interact with the cocaine.
00:37
B, he may have renal papillary necrosis from the
cutting agnet phenacetin in the cocain that he was using.
00:47
C, he may have taken Aspirin prior to using the cocaine,
and developed Reye's syndrome.
00:53
Or D, the anti-inflammatory he has taken
has caused interstitial hemorrhage in his kidney.
01:00
What's the most likely answer?
So he may have renal papillary necrosis from the
cutting agent phenacetin in the cocaine that he was using.
01:12
Now, let's take a look at this question.
Celecoxib may exacerbate renal dysfunction
but is unlikely to cause the clinical scenario here.
A is not correct.
01:23
B, it's believed that Howard Hughes died as a result of
a toxic side effect from phenacetin,
resulting in renal papillary necrosis and death.
B is the most likely answer.
01:36
Phenacetin is also linked with hemolytic anemia
in patients with G6PD deficiency.
01:42
This patient may be experiencing hemolytic anemia
as well as renal failure,
but the clinical picture isn't
consistent with that possibility at this time.
01:51
Reye's syndrome is associated with Aspirin use in children.
Now, most NSAIDs can cause an abnormality in clotting fomation,
but this scenario is unlikely at this time.
02:03
Let's go on to question number 2. A 66 year old woman
has been placed on methotrexate 7.5 mg once a week.
02:13
She also has folic acid supplementation. Methotrexate works
by the following mechanism in rheumatoid arthritis.
02:21
A, inhibition of folate kinase to increase
the free pool of folic acid.
02:28
B, inhibition of dihydrofolate reductase
to reduce the free pool of folic acid.
02:36
C, inhibition of folic synthase
to reduce the free pool of folic acid.
02:41
Or D, inhibition of folic reductase
to reduce the pool of folic acid?
Good. This is a hard question. But remember that
methotrexate inhibits dihydrofolic acid reductase
and that reduces the free pool of folic acid.
03:05
Let's do another question. Aspirin is unique
among the nonsteroidal anti-inflammatory agents because.
03:13
A, it is an irreversible binder to cyclooxygenase.
B, it is specific to the COX-2 form.
03:20
C, it is a suicide inhibitor of xanthine oxidase.
And D, it is a reversible inhibitor of dihydrofolate reductase.
03:30
Good, you chose irreversible binder. Remember that the other
nonsteroidal anti-inflammatory agents are reversible, Aspirin is irreversible.
03:39
So, the only way that you can get reversal of the effects of
Aspirin is by waiting for the platelets that are affected
or the agents that are affected to die off.
03:51
That's it. You've done very well to sit through this lecture.
I think that you're going to do very well on your exams.
03:57
Good luck.