Step I Amiodarone...class 1 or 3 ?

[mountaindew2006]

Advertisement - Members don't see this ad

Since FA has it listed as both...can someone say w/ certainity which one it actually is since the MOAs for each class is different.

😕 😕 😕

thanks guys

 

[bigfrank]

I had the same question. It is my understanding that Amiodarone actually possesses qualities of all four classes, but its primary action is class III and I. (It is initially Class III but is metabolized further to have significant Class Ia action.)

Because of the confusion regarding this drug's MOA, I would doubt that you would be asked a question regarding its MOA.

It is noteworthy, however, in being one of the few anti-arrhythmic drugs that is NOT pro-arrhythmic.

In short, if you are asked on the exam, it principally blocks K+ channels.

 

[scully]

It does have properties of all classes, but mostly 1 and 3 -- it blocks both sodium and potassium channels.

 

[mountaindew2006]

As always you guys rock!

and ladies

 

[southerndoc]

I had the same question. It is my understanding that Amiodarone actually possesses qualities of all four classes, but its primary action is class III and I. (It is initially Class III but is metabolized further to have significant Class Ia action.)

Because of the confusion regarding this drug's MOA, I would doubt that you would be asked a question regarding its MOA.

It is noteworthy, however, in being one of the few anti-arrhythmic drugs that is NOT pro-arrhythmic.

In short, if you are asked on the exam, it principally blocks K+ channels.

Right on! 👍

BTW, the benefit of amiodarone in v-fib is actually thought to be it's class II properties (this isn't its biggest affect though -- the primary drug effect is still class III and Ia). It's thought that alpha/beta blockade is helpful in v-fib, and this is currently being investigated with some IV alpha blockers.

 

[NateatUC]

Just as importantly, don't forget that it causes pulmonary fibrosis, contains iodine and thus causes hyperthyroidism (treat with PTU I believe), and can turn your skin blue!

I think I saw more pharm questions about drug side effects than about drug MOA's.