Ephedrine is a sympathomimetic amine - that is, its principal mechanism of action relies on its indirect action on the adrenergic receptor system, which is part of the sympathetic nervous system or SNS.("Fight or flight" system) While it may have weak agonist activity at α- and β-adrenergic receptors, the principal mechanism is to displace noradrenaline from storage vesicles in presynaptic neurons. The displaced noradrenaline is released into the neuronal synapse where it is free to activate the postsynaptic adrenergic receptors.
Ephedrine's mechanism of action on neurotransmission in the brain is wide. Its action as an agonist at most major norepinephrine receptors and its ability to induce moderate stimulation of the release of both dopamine and to a lesser extent, serotonin, is presumed to have a major role in its mechanism of action.
Because of ephedrine's ability to potentiate dopamine neurotransmission it is thought to have addictive properties by some researchers.
While ephedrine's role in the serotonin system is less understood there is preliminary documentation of clinically significant agonism at excitory serotonin receptors, perhaps as a downstream response to the large release of norepinephrine in the nucleus accumbens (commonly referred to as the "pleasure center" of the brain). In mice, stereotypical behaviour was both easily induced by administration of ephedrine and it's primary alkaloids and reversed when serotonin antagonists were administered.
Beta blockers (sometimes written as β-blockers) are a class of drugs used for various indications, but particularly for the management of cardiac arrhythmias and cardioprotection after myocardial infarction. Whilst once first-line treatment for hypertension, their role was downgraded in June 2006 in the United Kingdom to fourth-line as they perform less well than other drugs, particularly in the elderly, and there is increasing evidence that the most frequently used beta-blockers at usual doses carry an unacceptable risk of provoking type 2 diabetes.[
Beta blockers block the action of endogenous catecholamines, epinephrine (adrenaline) and norepinephrine (noradrenaline) in particular, on β-adrenergic receptors, part of the sympathetic nervous system which mediates the "fight or flight" response.
Beta blockers inhibit these normal epinephrine-mediated sympathetic actions, but have minimal effect on resting subjects. That is, they reduce the effect of excitement/physical exertion on heart rate and force of contraction, dilation of blood vessels, opening of bronchi, reduce tremor, and breakdown of glycogen.
It is therefore somewhat unexpected that non-selective beta blockers have an antihypertensive effect, since they appear to cause vasoconstriction. The antihypertensive mechanism appears to involve: reduction in cardiac output (due to negative chronotropic and inotropic effects), reduction in renin release from the kidneys, and a central nervous system effect to reduce sympathetic activity.
In sum ephedrine and B-blockers exhibit essentially opposite effects. Ephedrine promote norepinephrine excretion and B-blockers blocker the effects of excitation of Beta receptors (though generally not alpha receptors). It is impossible to entirely predict how these two agents will affect each other in you - but no matter, to some extent they will DIRECTLY interact with each other. In some ways they will cancel out each other's affect.
I hope this helps.
2006-10-04 14:09:42
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answer #1
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answered by c_schumacker 6
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It's good that you're asking these sorts of questions here. It indicates that you want to take an active part in your own care, which should always be encouraged! Hopefully the advice that people give you here will help you form good questions for your doctor the next time you visit. As others have said, exercise is definitely OK and recommended while taking beta blockers. However, it's good to know that they do, in fact, block your adrenoline response. So while you are probably used to jumping right in with your heart rate responding to adrenoline, you may now require a longer warmup to avoid feeling light headed. As to taking beta blockers for anxiety, I would be a bit concerned about that over the long haul. They're powerful drugs and you can't just go on and off of them willy nilly. If anxiety is causing your heart to race or go into some form of arrhythmia, then it's worth giving them strong consideration, but I would try to start with the lowest possible dose and only scale up if it didn't seem to be helping. And then, if it doesn't help after reaching target dosage, you need to slowly taper back off of it to avoid rebound problems. I would not personally resort to beta blockers until I understood the root cause of the problem. Has your doctor tried giving you a 30-day holter monitor? When you feel an episode, you can press a button and then download the data to the doctor. If your doctor doesn't have one of these devices, ask for a referral to a cardiologist who does. Good luck!
2016-03-18 04:40:48
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answer #2
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answered by Anonymous
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All I can say is just be real careful, thats like mixing bleach and ammonia. They dont go well together as far as i have been told!
2006-10-04 06:36:45
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answer #3
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answered by Anonymous
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