Chapter 37: Respiratory Drugs

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If you've ever, you know, felt that panic of struggling for breath, you realize pretty quickly that the error we normally just take for granted is, well, it's not simple at all.

Our respiratory system has this core job, right?

Get oxygen in, get CO2 out.

But that whole process can get really messed up by common problems like asthma and COPD.

And that struggle, that's really what we're digging into today.

We've done a deep dive into the pharmacology and the crucial nursing side of things for the drugs used to manage these lower respiratory tract conditions.

Okay.

Our sources lay it all out.

The, you know, the mechanisms, those tricky aterus effects, and maybe most importantly, the safety protocols, the things that really make or break patient success.

Yeah.

And our mission here is to try and cut through some of that complexity.

We want you, the listener, to walk away with the core stuff, the why behind the rules, you know?

So you don't just know what a drug does, but how to use it safely when you're actually with a patient.

Exactly.

So to start, let's just quickly frame the main issues.

We're mostly talking about two conditions here.

First, COPD, chronic obstructive pulmonary disease, which now kind of causes bronchitis and emphysema.

And the key phrase here is non -fully reversible airflow obstruction.

Once that damage is done,

well, we manage it, but we aren't curing it.

Okay.

So that's COPD.

Contrast that with asthma or bronchial asthma.

Right.

Asthma is different.

It's recurrent, often sudden, and crucially, it's reversible shortness of breath.

Reversible.

Okay.

And yeah, it involves bronchospasm, mucus fighting.

But the really big thing that guides how we treat it now is the underlying inflammation.

That's key.

Inflammation.

Got it.

And knowing that difference is vital because it really dictates which drugs we reach for and when.

And of course, the stakes get incredibly high if we're facing status asthmaticus.

That's that severe prolonged asthma attack that just isn't responding to the usual drugs.

It's a medical emergency.

Everything we talk about today really is aimed at preventing that.

Okay.

Makes sense.

So let's unpack this.

Where should we start?

Maybe with the first line of defense, this sort of immediate fix.

Yeah, let's do the bronchodilators first.

These are the drugs that relax the smooth muscle on the bronchi, open up those airways.

There are three main classes.

And the first one is probably the most famous, right?

The beta adrenergic agonists.

That's them, often called sympathomimetic bronchodilators.

Right.

Just means they mimic the effects of adrenaline or norepinephrine.

Okay.

Basically, they hit specific receptors, the beta adrenergic ones, and that stimulation activates a chemical messenger inside the cell, CMP, which tells the bronchial muscles to relax and dilate.

It's like flipping a switch to open the airways.

In this class, this is where that really critical safety difference comes in between rescue and maintenance use.

Absolutely.

You have the short acting beta agonists, SABO,

like albuterol is the main one, level buterol too.

Right, the rescue inhalers.

Exactly.

Fast onset, maybe half an hour, last three, four hours.

These are what you use for an acute attack.

Then you have the long acting ones, the laybiz, selmiterol for motorol.

Yep.

And selmiterol, for instance, its onset might take, you know, 30, maybe 45 minutes, but it keeps working for a full 12 hours maintenance.

Okay, 12 hours.

But here's the big warning sign.

Huge warning sign.

This needs repeating constantly.

Laybiz must never, ever be used for acute treatment.

They are purely for maintenance prevention.

Can you break down why that's so critical?

Because, you know, someone might think, well, it lasts 12 hours, surely it'll kick in eventually.

That's the danger,

the delay in onset.

If someone's having an acute asthma attack, gasping for air, and they grab their LABA inhaler, they're using a drug that provides zero immediate relief while their airways are actually closing up.

They might waste precious time, maybe even overdose thinking it's not working, or crucially delay using the SABO, the actual rescue drug they need right then.

Okay, that makes total sense.

It's about that immediate need.

Laybiz prevent the fire, they don't put it out.

Perfectly put.

They prevent the need for rescue, they don't provide it.

And what about side effects, even with the more selective ones like albuterol?

Yeah, even the beta 2 selective ones can cause issues, especially if overused.

You can see, like tremors, nervousness, maybe faster heart rate.

And if people use them too much, they can lose that beta 2 specificity and start hitting beta 1 receptors in the heart too.

Ah, okay.

And watch out for interactions, right?

Like with beta blockers.

Definitely.

Non -selective beta blockers can actually block the bronchodilating effect.

Yeah.

Using them with MAOIs or other sympathosomal mimetics, that could risk serious hypertension.

You have to be careful.

Got it.

Okay, let's move to the second class of bronchodilators,

the anticholinergics, or LMAs, long -acting musterinic antagonists.

Yeah, LMAs.

These work totally differently.

They block acetylcholine receptors on the bronchial tree.

Acetylcholine, that's the parasympathetic signal, right?

The rest and digest one that normally constricts airways.

Exactly.

So by blocking that constrict signal from the parasympathetic nervous system, these drugs indirectly cause the airways to relax and dilate.

Plus, they help dry up secretions, which is often a big plus, especially in COPD.

So primarily for prevention in COPD then, not for acute attacks because they're long -acting.

Precisely.

Their action is slow and prolonged.

The classic one is apetropium.

Atrovent.

Iapetropium.

And you mentioned something interesting about that one before.

A safety note that's changed over time.

I know, right?

Yeah, the source material points out that the older inhaler devices for apetropium used a propellant derived from soy lecithin.

So there used to be this contraindication or at least a strong warning for patients with peanut or soy allergies.

But that's basically gone now because the newer inhalers use HFA propellants, which don't have that issue.

Yeah.

It's a neat example of how the delivery tech changes safety considerations.

That is interesting.

But the standard anticholinergic side effects are still a thing.

Dry mouth, maybe urinary retention.

Oh yeah.

Dry mouth or throat is common.

Nasal congestion, sometimes palpitations, GI upset.

And you definitely need caution in patients with things like glaucoma or BPH because of potential increased intraocular pressure or urinary retention.

Okay.

Still long -acting, still not for rescue.

Got it.

That brings us to the third bronchodilator class.

The xanthine derivatives.

Mainly theorphine, right?

Though maybe use less now.

Yeah.

Theophylline is the main one, though definitely less common than it used to be.

Aminophylline is related.

It's basically a pro -drug

used IV sometimes like in status asmaticus.

And the mechanism here is different again, isn't it something about an enzyme?

Right.

Theophylline inhibits an enzyme called phosphodiesterase or PDE.

Think of PDE as the enzyme that breaks down CAMP -E, that relaxing chemical we mentioned with beta Oh.

So by blocking PDE, theophylline lets CAMP -E stick around longer, promoting smooth muscle relaxation.

It also has other effects.

It stimulates the central nervous system, which can help respiratory drive and the cardiovascular system too.

But this is the one with the really tricky therapeutic window, right?

Like very narrow, super narrow.

Traditionally, it was like 10 to 20 micrograms per milliliter, but most docs now aim for a tighter range, maybe five to 15 to minimize side effects.

You absolutely need blood level monitoring.

Which must make it tough to manage, especially with all the interactions it has.

It's a huge challenge.

I mean, think about it.

Cigarette smoking actually decreases the drug level because it speeds up metabolism.

Same with eating charcoal broiled foods or being on a low carb, high protein diet.

So we might need a higher dose in those folks.

Okay.

But then things like caffeine, certain antibiotics and macrolides like erythromycin or quinolones like Cipro and drugs like cementadine or towards toxicity and toxicity looks like nausea, vomiting first, maybe anorexia.

But then you get into serious stuff like sinus tachycardia or worse, ventricular dysrhythmias, even seizures at high levels.

So it's all in a favor compared to safer, easier to manage options.

Yeah, you can see why.

Okay.

That covers the bronchodilators opening the airways.

But you said earlier the real paradigm shift in treating these diseases, especially asthma was focusing on inflammation.

Exactly.

So now we move away from just dilating and focus on controlling that underlying inflammatory process.

These are the non -bronchodilating drugs used for long -term control.

And the first class here are the LTRA's, leukotriene receptor antagonists.

Right.

Drugs like Montelucas Singulair is the brand name many now.

Okay.

So leukotrienes are chemicals your body releases during inflammation.

They cause a nasty trio of effects, more inflammation, bronchoconstriction, and increased mucus.

LTRA's work by blocking the receptors that these leukotrienes bind to on immune cells.

So they stop the inflammatory signal from getting through.

Pretty much.

Reducing inflammation, which helps prevent asthma symptoms long -term.

They're also used for allergic rhinitis.

Key point though, these are strictly for prophylaxis, for prevention, right?

Not for an acute attack.

Absolutely not for acute attacks.

They take time to work maybe about a week before you see improvement.

They are purely maintenance therapy.

And Montelucas specifically.

There is a major safety alert we need to flag here.

Yes.

A very important one.

In 2020, the FDA put a black box warning on Montelucas.

Okay.

What for?

It's about serious neuropsychiatric events.

Things like agitation, aggression, anxiety, depression, sleep disturbances, and even suicidal thoughts and actions.

Wow.

That's serious.

It is.

So for any patient starting or taking Montelucas, you, the healthcare provider, and the patient and their family need to be really vigilant about monitoring for any mood or behavior changes.

The risk is significant enough to warrant that highest level of warning.

That's critical baseline assessment and ongoing monitoring then.

Okay.

LTRAs block leukotrienes.

What's the next major anti -inflammatory group?

Probably most powerful.

That would be the corticosteroids or glucocorticoids.

Think inhaled drugs like or butanide or systemic ones like prednisone or methylprednisolone.

And how do they tackle inflammation?

They have a kind of dual effect.

First, they are potent anti -inflammatories.

They stabilize the membranes of cells like mass cells and white blood cells, preventing them from releasing all those nasty chemicals that cause bronchoconstriction and inflammation.

Okay.

Stabilizes the cells.

And second, they actually help the beta agonists work better.

They seem to increase the responsiveness of those beta receptors.

But the full anti -inflammatory effect, especially with inhaled ones, can take several weeks to really build up.

Which explains why they are maintenance drugs.

So inhaled corticosteroids, ICS, those are the cornerstone for persistent asthma, right?

To keep things controlled day to day.

Exactly.

Using them inhaled is the preferred route for long -term control because it delivers the drug right to the lungs and minimizes the systemic side effects you get with oral or ID steroids.

Right.

So when do we use the systemic ones, the oral prednisone or IV methylprednisolone?

Really only for acute exacerbations or very severe asthma, when you need a rapid, powerful anti -inflammatory punch systemically.

But that comes with a significant cost in terms of side effects if used long -term or at high doses.

Let's talk about those side effects.

First, the local ones from the inhaled steroids.

What's the number one issue we need to watch for and teach patients about?

The biggest local problem is definitely oral candidiasis or thrush, a fungal infection in the mouth and throat.

Why does that happen?

Because the steroid suppresses the immune response locally, allowing candida yeast, which is normally present in small amounts, to overgrow.

Okay, and the absolute must -do intervention?

Non -negotiables.

The patient must rinse their mouth thoroughly with water and spit it out after every single dose of their inhaled corticosteroid, every time.

It physically removes residual drug from mouth and throat.

Rinse and spit, got it.

Now, the systemic side effects, especially with long -term or high -dose use, those are much more serious.

We're talking about increased susceptibility to infections,

fluid retention, mood changes, potential for bone loss leading to osteoporosis, thinning skin, cushioned appearance,

and a really big one is adrenal suppression.

Okay, adrenal suppression.

Let's focus on that because it leads to the most critical safety warning with systemic steroids.

Say a patient's been on oral prednisone for bad flare -up, they feel better, and they just stop taking the pills.

What happens?

That is potentially fatal.

It can trigger an adisonian crisis or acute adrenal insufficiency.

Because when you take external steroids for a while, your own adrenal glands stop producing cortisol, their natural steroid hormone.

They go dormant.

If you abruptly stop the external steroid, the adrenals can't just instantly wake up and start producing cortisol again.

And the body needs cortisol.

Critically.

For blood pressure, blood sugar, stress response.

Without it, you can get circulatory collapse, shock, and death.

That's why systemic steroids must always be tapered slowly under medical supervision, allowing the adrenal glands time to recover function.

Sometimes tapering takes weeks or even months.

Wow.

That really drives home the importance of patient education on adherence and never stopping steroids abruptly.

Just incredible.

It's one of the most important safety lessons in pharmacology.

Before we move to putting it all together in the nursing process, are there any other non -bronchodilating drugs we should quickly mention?

Yeah, a couple of others.

There's reflumelast, which is a phosphodiesterase 4 or PDE 4 inhibitor.

Different PDE than theophylline?

Yep.

Different subtype.

Reflumelast is used specifically to reduce COPD exacerbations, particularly in patients with severe COPD associated with chronic bronchitis and a history of flare -ups.

It helps decrease coughing and excess mucus.

Not for acute bronchospasm, though.

Definitely not.

And it also comes with a warning about potential psychiatric side effects, like mood changes and behavior issues, similar to montelucist, so monitoring is needed.

Okay.

And the newest players.

The biologics.

Right.

The monoclonal antibodies.

Drugs like omelizumab, epilizumab, and others.

These are typically add -on therapies for severe, difficult -to -control asthma.

How do they work?

Very targeted, right?

Very targeted.

They might bind to IgE antibodies, preventing them from triggering allergic reactions, or they might block specific interleukins, which are signaling molecules involved in inflammation.

They're given by injection, usually subcutaneous.

And the big risk with these?

Because they're proteins and modify the immune system, there's a significant risk of allergic reactions, including anaphylaxis.

Patients usually need to be monitored closely after administration, especially the first few doses.

Makes sense.

Okay, so we've covered a lot of The bronchodilators opening the airways, the anti -inflammatories tackling the root cause.

Now, let's bring it all together.

How do we apply this knowledge in practice, focusing on patient safety and making sure these treatments actually work?

It all starts with assessment, as always.

You need your baseline respiratory status rate, depth, rhythm, listen to those breath sounds, check pulse ox, but also look for subtle signs.

Like what?

Like restlessness or agitation.

That's often the very first sign that someone's becoming hypoxic, even before their O2 sat drops noticeably.

Don't just dismiss it as anxiety.

Good point.

And medication history is huge here, too, right?

Absolutely critical.

Prescription, OTC,

herbals.

And you specifically need to ask about caffeine intake because of those interactions with beta agonist and especially theophilium.

You also need specific baselines, depending on the drug class liver function for LTRAs, cardiac status for xanthines, maybe baseline mood for mothlucas or rafflumelast.

Okay, assessment done.

Now, implementation.

Technique seems paramount with inhaled meds.

It's everything.

If the patient can't use their inhaler correctly,

the drug doesn't get where it needs to go and it won't work.

Doesn't matter how good the drug is.

So what are the key teaching points for inhaler technique?

Like if they need two puffs of the same drug?

If it's two puffs of the same medicine, they should wait about one to two minutes between puffs.

This allows the airways to open a bit from the first puff so the second one can get in deeper.

Okay, one to two minutes for the same drug.

What if they're using two different inhaled drugs, like a rescue inhaler and an inhaled corticosteroid?

This sequence is vital, isn't it?

Absolutely vital.

The order is non -negotiable.

Bronchodilator first, then the corticosteroid.

Why that order?

You use the bronchodilator, the beta agonist, usually first to open up the airways.

It's like opening the door.

Then you wait about two to five minutes.

Okay, longer wait time there.

Yeah, give it a bit more time to work.

Then you take the inhaled corticosteroid.

Because the airways are now more open, the steroid medication can penetrate deeper into the lungs to treat the inflammation where it's actually happening.

Steroid first doesn't make sense if the door is closed.

Bronchodilator opens the door, steroid goes in.

Got it.

And we already hammered the point about rinsing the mouth after the steroid.

Can't emphasize it enough.

Rinse and spit after every ICS dose to prevent thrush.

And stress that these are maintenance drugs.

Take them every day as prescribed, even if you feel fine.

That's why you feel fine.

Okay, let's tie this back to a practical example.

You mentioned Advair earlier.

That's a combo inhaler with a Laba, some Metarol, and an ICS, Fluticasone.

Patients use it twice daily for maintenance.

Right.

So if that patient has sudden shortness of breath, what do they reach for?

Their separate albuterol rescue inhaler or the Advair?

They must use the albuterol, the Saba, the rescue inhaler.

Why not the Advair?

It has a bronchodilator in it.

Because the bronchodilator in Advair is salmetrol, a Laba.

And what do we say about Laba?

Never for acute treatment, slow onset.

Exactly.

Using Advair in an acute attack is ineffective and dangerous because of that delayed onset.

The albuterol provides the rapid relief needed.

The Advair is purely for prevention, taken twice daily, every day.

That distinction is probably one of the most common points of confusion and potential error for patients.

Rescue versus maintenance.

Huge.

And therapeutic success with the maintenance meds like Advair is measured by the patient needing their rescue inhaler less often.

Fewer symptoms, better activity tolerance, better peak flow readings if they use a meter.

Right.

Monitoring with peak flow meters and keeping a symptom journal can be really helpful for patients to see the benefits of that daily maintenance therapy.

Definitely.

Empowers them to manage their condition.

Okay.

So let's recap the big picture.

We've covered the three main types of bronchodilators.

The beta agonists, Sabas for rescue, Labas for maintenance with that huge safety warning.

The anti -colonogics, Lamecas, mostly for COPD maintenance.

And the xanthines, like theophiline, powerful but tricky with narrow window and interactions.

Yep.

Those are for opening the airways.

Then we hit the anti -inflammatories for long -term control.

The LTRAs like Montelucast, the black box warning for mood changes.

And the Powerhouse

Corticosteroids inhaled for daily maintenance.

Rinse that mouth.

And systemic for severe flare -ups.

Never stop abruptly, always taper.

Plus the newer guys, Roflumelas and the monoclonal antibodies for more severe cases.

Exactly.

A whole arsenal, but each with its specific place and crucial safety considerations.

So as we wrap up, what's a final thought for our listeners to chew on?

Something maybe challenging about managing these conditions long -term.

Something that's always fascinating and frequently difficult in practice is adherence.

Especially with the anti -inflammatory maintenance meds.

Why's that so tough?

Because drugs like inhaled corticosteroids and even LTRAs, they don't provide immediate symptom relief.

Their benefit builds up slowly, over days or weeks.

Patients feel better because they're taking them, but they don't get that instant feedback loop like they do with a rescue inhaler.

Ah, so when they're feeling good, they might think, eh, maybe I don't need this maintenance inhaler today.

Precisely.

The rescue inhaler gives instant gratification.

I felt bad.

I used it.

I feel better.

The maintenance inhaler prevents them from feeling bad in the first place, but that cause and effect is less obvious day to day.

So the real challenge, and maybe the final provocative thought, is getting patients to truly internalize that the symptom -free days aren't luck.

Exactly.

Those good days are the direct result of diligently using those preventive anti -inflammatory medications that are working silently behind the scenes.

The ultimate success relies on understanding that daily maintenance is the most important part of their rescue plan, preventing the attack before it even starts.

It's a fundamental shift from reactive to proactive care.

That's a powerful way to frame it.

Moving from just reacting to symptoms to actually controlling the disease process itself.

That's the core of chronic respiratory management.

Well, we hope this deep dive has helped to make these complex drugs a bit clearer and leaves you feeling more prepared.

Remember those key safety points and the why behind them.

Absolutely.

Take this knowledge, think about it, and go apply it safely and effectively.

Thanks for joining us.