beta blockers and medenephrine

[LA1989]

I figured I'd ask here b/c I'd get a quicker answer than from our doc.
Our cardiologist has prescribed atenolol (25mg) for Nick and has also requested a 24-hour urine test for pheochromocytoma. I was reading over the warnings with the atenolol and it says that it works by "blocking the action of certain natural chemicals in your body such as ephinephrine on the heart and blood vessels."
It also says to consult your doctor before using if you have "..........a certain type of tumor (pheochromocytoma)."

Should we ask about waiting to begin this beta-blocker until after the 24-hour urine collection is finished? Will starting it now possible skew the results?

[Heiferly]

If I could edit the title for you I would, but unfortunately I could only delete it and let you repost it, and that would only really help if we caught it right when you posted it and not after there was a whole conversation of replies following it.  Sorry.  :-/

If it makes you feel any better, I think it's pretty universal on MedHelp that we all make mistakes and realize them later and wish we could go back and edit; I usually just post a follow-up post in the thread sounding my "brain foghorn" and correcting the error.  :-p

Good luck with the test!

[LivingInHope]

Did some research and there was positive things said about urinary metanephrines but see PM for some info that might make you want to try the blood test first.

[LivingInHope]

Blood test is short and soon over (needs to be put on ice right away by the lab technician), while the urine has to go in the fridge- blood test would be much easier- but you may want to see if you can get the order from your primary doctor first before giving your son the option, just in case!  It would be nice if we could do editing when we see mistakes we've made- I've had some I've seen on myself too.  On the other hand, I wonder if they don't allow for changes in case a legal matter crops up or something?

[LA1989]

p.s. I really wish I could change the spelling of "metanephrine" in the title. I typed it late last night and didn't pay attention. That's going to drive me crazy.....

[LA1989]

I did hear back from the cardiologist this morning, surprise! He was vague in his answer, but I believe he advised us to wait till we get the other results.
I hear you about the plasma-free test. It's hard for me to talk this doctor into something other than what he suggests. I may have more luck with our primary care. I'm going to ask Nick which he would prefer, too, because frankly, he is very adverse to the idea of the urine collection. (he's a private guy...) But he hates to have his blood drawn, too, so we'll see which poison he would rather take. :)

[LivingInHope]

It makes a lot of sense to question whether to wait until he's done the test before taking a medication that blocks the action of epinephrine (metanephrine is the inactive metabolite of epinephrine, I believe what's left after the epinephrine is spent, and normetanephrine, the inactive metabolite of norepinephrine, which they also measure).  

But it sounds like from what you are saying that it doesn't block the emission of epinephrine, just the action it takes- I'd suggest if you don't hear quickly from your doctor you consult a knowledgeable pharmacist for their opinion.  Another idea is to consult the lab and ask if any instructions they have for preparation for the test include the avoidance of certain medications so many hours prior to testing that might skew the test results.  You are also supposed to avoid certain food prior to the urine test, I believe, such as vanilla.  

Also, the 24 hour metanephrines urine test is supposed to be pretty accurate, but the plasma free metanephrines if you look at most the literature on line out there in studies is shown to be the BEST test for ruling out pheochromocytoma.  I believe one medication to avoid for the fasting plasma free metanephrines is tylenol, as it interferes with assaying the levels.