Caffeine continues to have an effect as long as it remains in the blood. The critical factor is the metabolizing activity of substances in the liver known as enzymes.
A lower rate of metabolism means the drug remains in the body and produces its effects longer.
The half-life of caffeine-the amount of time it takes for the liver to remove half of the amount that has been ingested-varies considerably from individual to individual.
The usual adult half-life ranges from 2.5 to 10 hours, averaging about 4 hours. Most of the drug is removed from the body within 12 hours.
Men and women tend to have similar average rates of caffeine metabolism, as do people of all ages. Because of the liver's role in caffeine metabolism, most kinds of liver disease, particularly liver disease related to alcohol abuse, increase caffeine half-life.
Use of other drugs can dramatically affect the rate of caffeine metabolism.
On an average, smokers, whose caffeine half-life is approximately 3 hours, metabolize caffeine 50% faster than nonsmokers.
Thus, smokers experience the effect of a given cup of coffee for a shorter period of time than do nonsmokers. In addition, caffeine and nicotine have opposite effects on the neurotransmitter adenosine.
Perhaps smokers tend to drink more coffee than nonsmokers in order to compensate for these effects. -------------
Coco has caffeine, which is a vaso (something...dilate?constrict?). There may be other ingredients.
But, if you are unsure, call them in the a.m. and confess. And maybe trying to flush it out, and up your metabolism with some exercise? Also, according to the above article, smoking a cigarette will help speed metabolism of caffeine.....
Northstar
Posts: 1331 | From hither and yonder | Registered: Sep 2005
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Cobweb
Unregistered
posted
I'm having a SPECT scan of the brain tomorrow,too-but not at Columbia-and I was told there is no prep ! I even asked when i set up the appointment and the person said there wasn't any prep-i.e.-nothing about stopping caffeine, etc. So I am wondering now...
posted
I guess I didn't mention that I was a late stage
neuro lymie. I didn't understand any of that and
it was obvious that you put so much effort into your reply Northstar!
My husband is flying home tonight and happened to call me between connecting flights while I
was reading the reply. I told him, "There's this person that replied to my post and he/she sounds like they know what they're talking about
but I can't understand it. I can write a million words but can't comprehend more than a few I guess!
I read it to him, he understood it, tried to explain it to me but was on the plane and they were shutting the doors and telling people to shut their phones off....sooooo
are you telling me if I exercise tonight and drink water like crazy that there is a chance that the test won't be affected? The nurse said 24 hrs. I had something 15 1/2 hours before. I will call in the am. I just feel bad because my husband is cutting his business trip short just to fly home (arriving in the wee hours of the morning mind you) to drive me to Columbia. I just recently moved to NJ from Chicago area and have
hard enough time navigating around here locally. I would NEVER be able to drive into Manhattan and find this place!
I hope I don't have to cancel. This is a new job for my hubby. Bad time to take alot of days off or cut business trips short.
Thanks Northstar. Let me know what you think of the exercise drink water idea.
Posts: 70 | From essex fells, nj | Registered: Jul 2006
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northstar
Frequent Contributor (1K+ posts)
Member # 7911
posted
Hi Bugged,
If it were me, I would not worry. I would not drink excessive water, if I were in that situation. I would just drink normal amounts to be sure I had fluids in me.
If it were me, I would just go for a walk, or do something in the house to move the circulation, just to give the metabolism a boost. Nothing extraordinary.
This cocoa was drunk sometime this afternoon.
By the time you have the test, more than 12 hours will have passed, which is greater than the "clearance" time of 10 hours.
It looks to me like they are trying to prevent distortion of vasodilation/vasoconstriction in the brain by certain kinds of chemicals.
And if you are concerned, just mention it to the office in the a.m, with the number of hours that has passed.
Maybe there is a nurse on night duty there now who may reassure you?
Personally, I would not worry if it were me.
Just be sure not to do tea, coffee, or whatever they requested the rest of the time.
Sorry your husband is traveling in this messy weather.
I will fess up: I had 2 tablespoons of coffee the morning of a colonoscopy last year, and I did just fine.
Clean as a whistle and all that. (they do not want that because of the dark color which may stain the colon, as they told me)
I figured I earned it since they overdosed me on the meds, and I was up all night, passing out, bleeding, etc. And still had to be out of the house by 5 a.m. sparkly clean.
Take care, let it go, I am sure that you will be fine.
Northstar
Posts: 1331 | From hither and yonder | Registered: Sep 2005
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Cobweb
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posted
Hi Bugged-would love to hear how your experience went today with the SPECT SCAN. Carol
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posted
I was scheduled for the scan at 10:30 am but was there by nine. They were set to take me in
early but they started having problems with the scanner. They wanted to know if I wanted to
reschedule . I said I would like to stay and take my chances that the scanner would be
working again. They corrected the problem and I was scanned at around 1pm. For anyone that has
not had one, this is the process. First they take you into a room, give you an injection of
radiated fluid (a very small amount), then you lay down for 15 min (they turn the lights down
or off-whatever you prefer, but they have to be atleast turned down) You are not supposed to move or talk. This particular room is cold (other people have
said the same thing-so ask for a blanket before
the injection-as soon as you get in this room) Then they got me up and 30 min later I was
scanned. The scan itself took about
35-40 min. No clanking sounds like an mri. That was it. Make sure, while you are there and
before the scan is done, to ask the technician
for your own set of films for yourself. It doesn't cost anything when you get them the day
of the test. It costs later when they have to
pull them from their hospital library and make copies. They couldn't give me a copy of the
report because it was not going to be read until later tonight. I did the same thing yesterday
for my brain mri. They gave me my own set of films and I signed a paper requesting a copy of
the report. You can have it sent to your home or can pick it up in the office. I told them I
lived close, so I would pick the report up today. If you make those arrangements ahead of
time they are very accomodating.
The FIRST thing they asked me when I checked in was if I had smoked (nicotine), ate chocolate or
had anything with caffeine in the last 24 hrs. I asked a nurse there in the nuclear dept if it
would mess up my test if I had a cup of hot cocoa at 5 the night before. She said it was not a
problem, asked if I had any caffeine this morning, I replied no, and she said that I would
be fine for the test. I had the cocoa 15 hours before the test and it
was just that, so they said that it wouldn't
affect the test. The cocoa was a misstep on
my part so I think you should avoid caffeine, etc
for the entire 24 hours, just to know that you
are not doing anything to compromise your test.
I have an appt with the llmd next wed to discuss both tests.
I hope that takes the mystery out of spect scans for anyone that hasn't had one.
robi
Frequent Contributor (1K+ posts)
Member # 5547
posted
Thanks so much for this. I go wednesday for mine. This really helped me a lot.
robi
-------------------- Now, since I put reality on the back burner, my days are jam-packed and fun-filled. ..........lily tomlin as 'trudy' Posts: 2503 | From here | Registered: Apr 2004
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Cobweb
Unregistered
posted
Hey Bugged-we were on the table at the same time!
My head was resting in a special craddle and they strapped it down so I wouldn't move. Fortunately the itching that popped up on my face did not last long, nor was it too intense, cause I didn't dare scratch.
I was peacefull enough during the initial "rest period" and they gave me a warmed blanket-I love those-wish I could duplicate them at home.
They also gave me "thigh wings!" You know, the table was kind of narrow, so they inserted plastic molded trays on either side of my thighs, so I had a place to rest my arms. Wonder if that's necessary for everyone.
As I said, I was peaceful enough before hand, but after they gave me the injection, which did not hurt at all,I noticed during the test that my heart was pounding hard enough for me to feel it and I could feel the pulse in my head. Had a bit of a headache, but I have been getting headaches anyway.
I wondered if anxiety was going to screw up the test since the pounding heart was going to force the blood into my brain more and show a greater blood flow.
I wish I had been more assertive about films. They wouldn't even show me a picture on the monitor, and said my doctor(s) would be in touch when they got the results.
Driving home I had this deja vu feeling of someone informing me that my films were lost, misplaced,whatever-and it was all for naught. Bummer !
Thursday I go for a diagnostic mammo and a bone density scan, but they said the radioactive isotope would be clear of my system by then.
Meanwhile..we wait-the hardest part. Carol
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I got my SPECT scan done on Thursday. I asked and I was told there was no prep. No one told me no caffeine, no nicotine. I was given the injection, but not told to lie down or close my eyes or not talk. I was sitting up in a bright room talking to my hubby.
They did the test by having me lie down for 40 minutes perfectly still. They gave me something to hold onto so I wouldn't move my arms. I had to ask them to put a strap over my feet and across my chest to help me not to move.
The first time I called to set up the appt., no one even knew what it was. My dr.'s office called them, then called me and said they know what it is. However, the techs seemed slow and unsure of what they were doing compared to CT scans I've had before.
I hope the scan is accurate considering that they didn't tell me how to do it.
Does anyone know if adrenalin could affect the SPECT scan? I hurt myself on the way to the hospital and had a surge of adrenalin.
Thanks for your help! Kayda
Posts: 582 | From midwest | Registered: Nov 2006
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Cobweb
Unregistered
posted
Guess we'll find out if adrenalin plays a part in the results. I had sort of an anxiety attack during the test and had this sudden impulse to sit up ,start screaming , push the machine away, and start flailing my arms around like I was swating mosquitos.
I've had MRI's in the tunnel with no problem-actually fell asleep. And as you know the SPECT is an open test-not in an enclosure.So I don't know what prompted this reaction, except that I'm a basket case. I really had to do a lot of mental gymnastics to stay imobile.(seems like a contradiction there).
posted
last year when they strapped my head in place, i went ballistic; NO WAY; so they had to do this in hospital with me being completely under!
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hshbmom
Frequent Contributor (1K+ posts)
Member # 9478
posted
My daughter will have a brain spect scan next Tuesday.
The injection burned up through her arm when she had an MRI. She's afraid this injection will burn too.
Did your injection burn?
I think the injection may have gone through the vein. I don't think it was supposed to burn.
How did it feel?
Nancy
Posts: 1672 | From AL/WV/OH | Registered: Jun 2006
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The tech asked me if the tracer substance burned. I said, "No, not yet." They said, they didn't want it to burn ever and not even a little.
I did get a weird taste in the back of my throat. Some people do, some don't.
Sound like your daughter had a little trouble with the MRI tracer, well, actually that the tech had trouble administering it to her.
Kayda
Posts: 582 | From midwest | Registered: Nov 2006
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Cobweb
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posted
No I did not feel any burning from the tracer injection.It was done at the crease of my right elbow-where they usually draw blood.
It certainly was not anything like having blood drawn-sometimes that goes easily and sometimes it doesn't.
I was pleasantly surprised at how minimally I felt the injection. They did put a cotton ball on it and had me fold my arm up while waiting for the tracer to racer through my system.
Really -as compared to an MRI , the SPECT was a piece of cake. I did get a slightly funny taste in the back of my mouth-but again no big deal.
Be sure to ask for a warm blanket!
Carol PS I have also had a PET scan done a while ago and the tech told me this tracer was similiar , but not as strong. Also -it has a certain half life, so it is important to be early or on time, as they have to order the tracer the day of the test, it's expensive, and they didn't want to waste it.
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