beta blockers vs. albuterol

[zzyzx]

If a patient is on beta blockers, how effective will albuterol be?

[VentMedic]

You will still get some bronchodilation. I see this often in the Pulmonary Lab since the majority of the older pts are on a beta blocker and 3 puffs of albuterol can produce nice results. IV Beta blockers may give albuterol a harder time competing for the receptors. Inderal used to be the Godmother of all beta blockers and put up the biggest fight.

However, high dose nebulized albuterol (10 - 20 mg) given very quickly in an aerosol sparing/Breath activated neb such as the Aeroeclipse can be used for beta blocker OD. On our inhouse ER/ICU protocol we can go up to 40 mg of 0.5% albuterol for beta blocker OD or hyperkalemia. Of course, for our Canadian and European friends who can use IV albuterol...0.5 mg IV albuterol can trump all.

[crazycanuck]

The answer to this question depends on a whole lot of variables.

The short answer in general is that it may take more albuterol to relieve SOB in a person who is also receiving beta blockers.

As you know there are Beta 1, 2, and 3 receptors. You're most concerned with beta 1 (heart) and beta 2 (lung) mechanisms. A beta blocker (antagonist) comes in two basic categories: beta 1 selective (cardioselective) or non-cardioselective. Some examples of cardioselective beta antagonists are bisoprolol, atenolol, metoprolol. Some non-cardioselective are: nadolol, labetolol, sotalol(also class3 antiarrhythmic properties). Non-cardioselective beta antagonists are contraindicated in patients with prior hx of mod-severe asthma or other resp problems.

The amount of affinity for the beta receptors, or cardioselectivity is proportional to the dose. So even if a patient is taking a cardioselective beta antagonist, if they get to a high enough dosage, there will be spillover to the beta 2 lung receptors.

Now, getting to albuterol, it is an inhaled B2 agonist. If a patient is taking a beta blocker that is already blocking the receptor then the intuitive answer is that the response to the inhaled B2agonist will be reduced. Getting into non-competitive and competitive antagonism- I'm not sure if the B2 agonist albuterol will override the blockade, I don't think it does but that discussion is over my pharmacology knowledge.

So- the answer is kind of beating around the bush but it really depends on a lot of things- the dose and type of the beta blocker, the severity of the SOB, the amount of albuterol administered, etc.

I'm sure someone else will give you some more hands on knowledge of this and their experiences in use of both meds concurrently.

Hope that helps.

*Edited to replace "the obvious answer is" to "the intuitive answer is" :wink:

[Dustdevil]

Plus 5 for an awesome question and topic!

This is what it's all about! :thumbright:

Minus 5 to me for hijacking by posting this non-contributory reply.

[kevkei]

Plus 5 for an awesome question and topic!

This is what it's all about! :thumbright:

Agree'd. Good posts too by crazycanuck and Ventmedic.

If you are in need of beta II activation to mitigate bronchoconstriction, you can also go different routes. It isn't going to hurt to use the albuterol, as was pointed out, you have to consider the affinity of the antagonist (betablocker) and the agaonist (albuterol). Although the betablocker has higher affinity to bond, it can be displaced by a higher concentration of the albuterol. You can also look at an agent that has a higher natural affinity at lower doses, like epinephrine. You can also consider the route of administration, SQ, IM, IV or you can also nebulize epi.

I would add that this is where adding another class of drug would help too. Atrovent (Ipratropium bromide) would be beneficial as would Mag Sulfate as well as a steroid.

I guess part of the question is, why do you ask? Are there limitations to what you can do? Is it a theoretical question looking for an answer? General interest?

[akroeze]

Can I ask a follow-up question?

Say I'm on scene treating a severe SOB with wheezing via ventolin. I see that the ventolin has little to no effect but realise the patient is on ventolin. Woudl I looked at as if I was crazy if I were to patch to the doc and ask for direction (possible epi?) on this case? I'm asking more in an Ontario perspective.

[kevkei]

Can I ask a follow-up question?

Say I'm on scene treating a severe SOB with wheezing via ventolin. I see that the ventolin has little to no effect but realise the patient is on ventolin. Woudl I looked at as if I was crazy if I were to patch to the doc and ask for direction (possible epi?) on this case? I'm asking more in an Ontario perspective.

I don't think you would look crazy at all. I think it takes more intelligence to recognize something outside of your comfort zone and want to get direction than not recognize that what you are doing isn't working and effective and keeping on. It shows you are thinking outside of the box. Especially if it falls outside of your standing orders/protocols. For example, you don't have a protocol for epi in asthmatics but you do for anapylaxis.

[Lithium]

Actually, Ontario does have a protocol for Epi use in asthma, as well as anaphylaxis and croup.

Long-story short ... akroeze, depending how severe you thought your patients SOB is, you could probably get away with using Epi to relieve their symptoms. Espeically if you've already maxed out your ventolin protocol and still have a while before arrival at the ED (as can be your case up north).

Don't be afraid to patch, the most they'll say is no.

Jacob

[akroeze]

Actually, Ontario does have a protocol for Epi use in asthma, as well as anaphylaxis and croup.

Long-story short ... akroeze, depending how severe you thought your patients SOB is, you could probably get away with using Epi to relieve their symptoms. Espeically if you've already maxed out your ventolin protocol and still have a while before arrival at the ED (as can be your case up north).

Don't be afraid to patch, the most they'll say is no.

Jacob

The only issue with working under protocol is that they have to be requiring assisted ventilations. Other than that, I understand

[Lithium]

Yes, I am fully aware of what the conditions are :wink: , but if your patient is in extremis as you put it, I would assume you were heading that way if not already there.

Back on the original topic however ...