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  #1  
Old 09-23-2012
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Drug Partial Beta Agonists and Angina!

Hey everyone!!

Can someone explain to me why partial beta agonists like pindolol and acebutolol are contraindicated in angina??!!

Thank u!!
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Old 09-23-2012
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pindolol and acebutalol are beta blockers with intrinsic sympathomimetic activity....their actions become similar to epinephrine at higher doses only (anyhow their agonist activity is limited though)...at lower doses they act as beta blockers..i.e the reason they are not chosen for angina/asthma

but if you want to give/choose a beta blocker for asthmatic or angina pt. then acebutalol or pindolol are the best choices to give...
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Old 09-23-2012
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Quote:
Originally Posted by venky2600 View Post
pindolol and acebutalol are beta blockers with intrinsic sympathomimetic activity....their actions become similar to epinephrine at higher doses only (anyhow their agonist activity is limited though)...at lower doses they act as beta blockers..i.e the reason they are not chosen for angina/asthma

but if you want to give/choose a beta blocker for asthmatic or angina pt. then acebutalol or pindolol are the best choices to give...
Venky, won't they be contraindicated because (being partial agonists), they can become antagonists in the presence of an agonist, and hence trigger vasoconstriction? My understanding of partial agonists is that they have lower efficacy than a full agonist, but will become an antagonist in the presence of a full agonist (For instance, in this case, epinephrine?) Please correct me if I'm wrong!

Last edited by dockhi; 09-23-2012 at 06:30 AM.
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Old 09-23-2012
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Quote:
Originally Posted by venky2600 View Post
pindolol and acebutalol are beta blockers with intrinsic sympathomimetic activity....their actions become similar to epinephrine at higher doses only (anyhow their agonist activity is limited though)...at lower doses they act as beta blockers..i.e the reason they are not chosen for angina/asthma

but if you want to give/choose a beta blocker for asthmatic or angina pt. then acebutalol or pindolol are the best choices to give...
What you mean by this bolded statement.

Acebutolol and pindolol are partial agonist with Intrinsic sympathomatic activity. So they cause less bradycardia (not as effective as complete beta blockers) , slight vasodilation (increases CO)

So i think
For Angina: B1 selective blocker (Atenolo, Metoprolol) > B blocker (propranolol)????

For asthmatic with angina: non selective B blocker ????
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Old 09-23-2012
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Quote:
Originally Posted by koolkiller88 View Post
What you mean by this bolded statement.

Acebutolol and pindolol are partial agonist with Intrinsic sympathomatic activity. So they cause less bradycardia (not as effective as complete beta blockers) , slight vasodilation (increases CO)
Quote:
Originally Posted by koolkiller88 View Post


So i think

For Angina: B1 selective blocker (Atenolo, Metoprolol) > B blocker (propranolol)????

For asthmatic with angina: non selective B blocker ????


yes koolkiller you are true indeed(sorry didnt mention abt selectivity)......what i'm saying is generally cardioselective beta blockers(not cardioselective) are used for angina,nonselective are contraindicated because of beta 2 activity.....but acebutolol and pindolol are better choices than nonselective beta blockers(implies generally for pindolol as it is non selective) in pts who suffer from asthma or angina..

pindolol cannot be given for angina/asthmatic in low doses(coz it worsens by beta 2 blockade) it is given in higher doses

Quote:
Originally Posted by dockhi View Post
Venky, won't they be contraindicated because (being partial agonists), they can become antagonists in the presence of an agonist, and hence trigger vasoconstriction? My understanding of partial agonists is that they have lower efficacy than a full agonist, but will become an antagonist in the presence of a full agonist (For instance, in this case, epinephrine?) Please correct me if I'm wrong!
ya you are true but when used with agonists....these 2 drugs show agonist activity only at high doses......if we got a condition to choose a beta blocker for hypertension who is known asthmatic then these are bettr choice than the other,by making sure he is not in agonist drugs.....we dont give agonists to him....
i may not be 100% sure...i'm just telling what i knew...
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Quote:
Originally Posted by venky2600 View Post

yes koolkiller you are true indeed(sorry didnt mention abt selectivity)......what i'm saying is generally cardioselective beta blockers(not noncselective) are used for angina,nonselective are contraindicated because of beta 2 activity.....but acebutolol and pindolol are better choices than nonselective beta blockers(implies generally for pindolol as it is non selective) in pts who suffer from asthma or angina..
.
typo here.....and as pindolol must be given in high doses to achieve beta agonist activity,they are usually not chosen(but if you have to choose anyway,they are the best choice)
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