Chapter 25: Analgesics & Pain Management Drugs

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Welcome back to the Deep Dive.

We are so glad you're here because today we are heading into the absolute trenches of nursing practice.

We really are.

We aren't looking at obscure diseases that you might see once in a career or rare treatments that only exist in specialized research centers.

We are looking at the one thing, the one universal element that you are guaranteed to encounter on almost every single shift, regardless of where you work.

It is the universal language of healthcare, really.

I mean, whether you're in the ER, the ICU, pediatrics or geriatrics, this is the common denominator.

Absolutely.

We are tackling Chapter 25, Analgesics from Pharmacology, a patient -centered nursing process approach, the 12th edition.

And honestly, just looking at the stack of notes and the chapter itself, this feels, it feels heavy.

It should feel heavy.

Not just technically heavy because there is a lot of chemistry here, but ethically heavy.

It should.

You know, when we talk about antibiotics, we're fighting bacteria.

When we talk about antihypertensives, we're fighting, you know, blood pressure physics.

But with analgesics, we are fighting suffering.

And that brings a level of responsibility that is really unique in pharmacology.

We are managing the patient's comfort and their ability to heal, which creates a very, very distinct pressure on the nurse.

That is the mission for this deep dive.

We are going to strip away the confusion.

We're going to take the textbook definitions from this 12th edition and translate them into what I call clinical survival skills.

I like that.

We want to make sure you understand not just what to give because memorizing a drug name is easy, but why you're giving it and crucially how to do it without hurting someone.

And we are going to be very disciplined today.

There is so much folklore out there about pain management.

You know, what your grandmother told you about whiskey and honey or what you saw in a medical drama TV show.

Right.

We are pushing all that aside.

We are sticking strictly to the provided text.

If it's not in the chapter, it's not in this conversation.

This is about getting you ready for your exams and for safe evidence based practice.

So let's start at ground zero.

The definition.

We all know what pain feels like.

If I stub my toe, I know I'm in pain.

But how does a medical textbook actually define it?

Because ouch probably doesn't cut it on a licensure exam.

Ouch is a start and it's valid, but the text is very specific.

It defines pain as an unpleasant sensory and emotional experience related to tissue injury.

Okay.

I want to pause on that middle part.

Emotional experience.

That feels like a very intentional choice of words by the authors.

It's crucial.

It is so crucial.

The text is telling us right up front that pain isn't just a signal traveling up a wire, like a telephone line.

Right.

It's not just data.

It's not just a broken bone or an incision sending data.

It is a subjective experience.

It impacts the mind as much as the body.

And because it's subjective, it presents a massive challenge for the nurse.

You can't measure it with a thermometer like a fever.

You can't see it on an x -ray like a fracture.

You have to rely on the patient.

Which leads us to that famous phrase that the Joint Commission TJC really pushed into the spotlight.

You see it on posters in every hospital hallway.

Pain is the fifth vital sign.

It sounds a little like a marketing slogan, doesn't it?

But it actually changed policy.

It changed everything.

It fundamentally changed the workflow and the expectation of care.

The Joint Commission incorporated pain assessment, documentation, and management directly into their standards.

So just like you wouldn't dream of skipping a blood pressure check or counting a heart rate.

You can't skip the pain assessment.

You cannot.

The nurse's role is clearly defined.

Assess it, alleviate it using both pharmacologic and non -pharmacologic methods, and then critically document the response.

That documentation piece is where people get tripped up.

It's not enough to just give the pill and walk away, is it?

No, not at all.

If you give a medication for blood pressure, you recheck the blood pressure to see if it worked.

Of course.

The same applies here.

You have to prove it worked or you have to document that it didn't so the plan can change.

You have to close the loop.

Exactly.

Now, before we get into the actual drugs, we have to clear up some vocabulary.

There are two terms that students mix up constantly, and I think even some working nurses use them interchangeably when they really shouldn't.

Pain threshold and pain tolerance.

They sound like synonyms in casual conversation, but in pharmacology, they are definitely not.

Let's start with pain threshold.

This is physiological.

It is the level of stimulus needed to create a painful sensation.

So this is the mechanics of the body, the hardware.

Right.

And the text drops a really fascinating scientific nugget here that I think helps explain why people react so differently to the same injury.

It links pain threshold directly to your genetics.

That was surprising to me.

So when someone says, I have a high pain threshold, they might actually be bragging about their DNA.

They might be, whether they know it or not.

The text points to the mu opioid receptor gene.

The gene controls the number of u receptors.

You can think of them as the landing pads for pain relief that you have in your body.

Some more landing pads.

If you are genetically lucky and have a large number of these new receptors,

your pain threshold is physically higher.

It takes a stronger punch, a hotter surface, a deeper cut for your nerves to send that pain signal to your brain.

Your sensitivity is literally turned down at a genetic level.

So that is hardwired.

You can't really train your threshold.

It's just the equipment you were born with.

Essentially.

Yes.

Now let's flip that over to pain tolerance.

This is the amount of pain a person can endure without it interfering with their normal functioning.

Okay.

So this is not about the receptors.

No, this is psychological.

This is subjective.

This is the software.

This is the mind over matter part.

Precisely.

And the text lists a huge menu of factors that influence this.

Your age, sex, culture, ethnicity, your anxiety level, previous experiences with pain.

So if you're terrified because you don't know what's happening, your tolerance goes down.

It plummets.

But if you come from a culture where stoicism is valued, your tolerance might appear higher because you've been socialized not to show it, even if you're feeling the same amount of pain.

So threshold is the hardware.

Tolerance is the software.

That is a perfect analogy.

And knowing the difference helps us understand the patient.

Just because two patients have the same surgery doesn't mean they have the same threshold or tolerance.

It's why we can't have a one -size -fits -all approach.

And the text notes that we stratify our analgesics based on this reality.

Mild to moderate pain gets non -opioids.

Right.

And moderate to severe pain gets the heavy artillery,

the opioids.

Okay.

So we need a roadmap of the enemy before we attack it.

The chapter classifies pain in two main ways, by duration and by origin.

Let's tackle duration first.

Acute versus chronic.

This seems simple.

Short versus long.

But the clinical implications are totally different.

They are worlds apart.

Acute pain is sudden.

It usually has a specific onset and a short duration.

The book defines it as less than three months.

So I broke my arm.

I had surgery.

I have acute pain.

Right.

And the goal there is cure.

You expect it to get better.

It responds to treatment.

You treat the injury.

The pain goes away.

Simple enough.

But chronic pain.

Chronic pain is the beast.

It's often vague in origin.

It has gradual onset.

And it persists for more than three months.

And the text implies that chronic pain becomes more about management than cure.

Exactly.

It's long -lasting discomfort that wears a patient down psychologically, emotionally, spiritually.

You aren't necessarily fixing it in the same way.

You're trying to give the patient their life back despite the pain.

Now let's look at origin.

Not -susceptive versus neuropathic.

This is where the biology gets really interesting.

Not -susceptive is your standard, I got hurt pain.

Correct.

Not -susceptive pain comes from tissue injury.

But we can split that hair even further.

The book divides it into somatic and visceral.

Okay.

Somatic is the body framework, right?

Like the skeleton and muscles.

Yes.

Structural tissues.

Bones, muscles, ligaments, skin.

If you twist your ankle, that's somatic -ness -susceptive pain.

It's usually sharp, localized.

You could point to it with one figure and say, it hurts right here.

And visceral.

Visceral is the organs,

the viscera, smooth muscle.

Think of a kidney stone or appendicitis.

It's often described as dull, aching, deep, and it's much harder to pinpoint.

A patient might rub their whole abdomen rather than pointing to a single spot.

That makes sense.

Okay, so that's not -susceptive, tissue damage.

Now a neuropathic pain sounds like a wiring problem.

That is exactly what it is.

The text calls it a neural supersensitivity.

It's caused by injury or disease of the nervous system itself.

The tissue might have healed completely, but the nerve is still screaming.

So the patient won't say, it aches?

No.

They will use very specific, descriptive words.

The textbook lists them.

Burning, tingling, shooting, or electric shock sensations.

These are classic neuropathic words.

The text gives some classic examples that we see in the hospital all the time.

Diabetic neuropathy is the big one for the peripheral nervous system.

The patient's feet burn and tingle, even though there's no new injury.

And for the central nervous system, think of a herniated disc pressing on the spinal cord, or a spinal cord injury itself.

The nerve path is damaged.

So why does this distinction matter so much?

Why can't I just throw morphine at all of it?

Because they don't respond the same way at all.

Neuropathic pain is notoriously resistant to standard painkillers.

If you give a standard opioid for that burning nerve pain, you might sedate the patient into a coma before you actually stop the burning sensation.

Wow.

You need different tools.

You need drugs that specifically target the nerves, which we'll get to later.

Which brings us to the mechanism.

How does the signal actually travel from the toe to the brain?

The text brings up the gait theory by Melzack and Wall.

1965.

This is the grandfather of pain theories.

It's a bit abstract, so let's try to visualize it.

You have a tissue injury.

Let's say you hit your thumb with a hammer.

That injury activates nociceptors, the pain endings in your thumb.

This triggers a chemical explosion.

The text lists a whole soup of mediators that get released.

Like what?

Substance P, prostaglandins, bradykinin, histamine, serotonin, a whole cascade.

It's like kicking a beehive inside the tissue.

It is.

These chemicals lower the threshold of the nerve endings.

That makes them super sensitive.

Then they initiate an electrical signal, an action potential, that shoots up the sensory nerve fiber toward the spinal cord.

And this is where students need to pay attention.

Because there are two distinct lanes on this highway to the spine.

The A delta fibers and the C fibers.

Yes.

A delta fibers are the express lane.

They are myelinated.

Myelin is like the insulation on a wire, right?

It speeds up the electrical conduction.

Exactly.

It's a fatty sheath that allows the signal to jump.

So A delta fibers transmit rapid acute pain.

This is that immediate sharp breathtaking ouch when you touch a hot stove.

It's the warning signal that makes you pull your hand back.

And the C fibers?

C fibers are unmyelinated.

They're the slow local lane.

They transmit impulses slowly.

They're responsible for that dull throbbing aching pain that sets in 10 minutes later and lasts all day.

So the sharp ouch is A delta and the long lingering ache is C fibers.

You got it.

So the signal travels up these fibers to the spinal cord.

And this is where the gate is, according to the theory.

In the dorsal horn of the spinal cord.

Right.

If the gate is open, the signal goes up to the brain, and your brain says, my thumb hurts.

If we can close the gate, the signal stops there.

No brain involvement, no perception of pain.

And our drugs are essentially gatekeepers.

They are.

And they work at different points along this whole pathway.

This is what the chapter calls the chemical blockade.

Okay.

Let's map the drugs to the physiology.

This is good stuff.

Okay.

Opioids.

They work centrally.

In the CNS, the brain and spinal cord, they activate receptors that mimic our body's natural endorphins to block the signal's perception in the brain.

They basically tell the brain, don't worry about that signal from the thumb.

So they close the gate from the top down.

What about NSRs, like ibuprofen?

They work peripherally at the site of injury back in the thumb.

They block an enzyme called cyclooxygenase, or COX.

By blocking COX, they stop the production of those prostaglandins that were sensitizing the nerves of the...

Cortisone is a powerhouse.

It goes even higher upstream.

It blocks an enzyme called phospholipase, which reduces both prostaglandins and leukotrenes.

It shuts down the whole inflammatory cascade before it even starts.

And for that electric neuropathic pain we talked about?

That's where anticonvulsants come in.

They don't mess with the inflammatory suc.

They work directly on the nerve fiber itself.

They inhibit nerve impulses by stabilizing the neuronal membrane and inactivating sodium channels.

They just tell the nerve to be quiet.

They essentially tell the nerve, stop firing so much.

Calm down.

It's impressive.

We have the sophisticated arsenal.

We understand the pathways.

We have the drugs.

And yet the text highlights a really dark statistic under treatment.

It's the paradox of modern pain management.

We have all these amazing tools, but we aren't using them well.

The text cites that post -operative pain is inadequately managed in over 80 % of patients in the United States.

Wait, 80 %?

8 -0.

That means if I have surgery tomorrow, there is a massive statistical probability I'm going to be in unnecessary pain.

According to the text, yes.

And it's not just uncomfortable.

It has real physiological consequences.

The text lists them out.

Increased heart rate.

Increased blood pressure.

Fluid overload.

Electrolyte imbalance.

Hyperglycemia.

Pain literally stresses the body into a state of disease.

It delays recovery.

Delays recovery, increases hospital costs, causes psychological trauma.

It's a huge problem.

So why is this happening?

Is it just that we're stingy with the meds?

It's complicated.

The text lists several barriers.

Sociocultural variables.

Maybe the patient doesn't want to complain because they think it makes them a bad patient.

Or they don't want to bother the busy nurse.

Right.

Then there's the fear of substance use disorder.

Patients are terrified of getting addicted, so they refuse meds they actually need for acute pain.

But the big one, the one that falls on us, the nurses and providers, is the inability to measure pain accurately, or worse, an unwillingness to believe the patient's report.

That bias.

Oh, he doesn't look like he's in pain.

Exactly.

He's on his phone scrolling social media, so he must be fine.

The text warns against this so strongly.

We use the zero to ten scale for a reason.

Zero is no hurt.

Ten is the worst.

If a patient says it's a nine and you give a med, and 30 minutes later they say it's a seven.

That's progress.

That's data.

It is measurable progress.

Even if they are still in pain, you have data.

You have to trust the patient's report over your own assumption.

That is the core message of patient -centered care in this textbook.

Let's get into the toolkit then.

We are starting with section two, non -opioid analgesics.

These are your frontline soldiers for mild to moderate pain.

The book lists examples like dull, throbbing headaches, arthritis, dysmenorrhea, which is maestral cramps, minor abrasions.

These are less potent than opioids, but don't let that fool you.

They are powerful drugs.

And the heavy hitter here is the NSAID group, non -steroidal anti -inflammatory drugs.

Aspirin, ibuprofen, naproxen.

And their mechanism of action is inhibiting that COX enzyme we talked about.

But, and this is a huge but for exams and for your understanding of side effects, there are two forms of this enzyme.

COX -1 and COX -2.

You absolutely need to understand the difference to understand what happens to the patient.

Let's break them down.

Let's call COX -1 the housekeeper, the good guy.

I like that.

COX -1 is the housekeeper.

It does good things.

It protects the stomach lining by producing mucus and bicarbonate.

It regulates blood playlists to help with clotting.

It keeps things running smoothly.

And COX -2.

COX -2 is the troublemaker.

It only shows up when there's an injury.

It triggers inflammation and pain.

So in a perfect world, we would build a drug that only shoots the troublemaker, COX -2, and leaves the housekeeper, COX -1, alone.

That is the dream.

That's what drugs like silicoxib try to do.

But the traditional NSAIDs, like aspirin and ibuprofen, they're not selective.

They're like a shotgun.

They block both.

So you lock COX -2, and yay, the pain and inflammation go away.

But you also block COX -1.

And the stomach lining loses its protection.

That leads directly to gastric irritation, ulcers, and GI bleeding.

And because you're affecting the platelets, you lose some clotting ability, so you bleed easier.

That's the trade -off.

Let's talk about the oldest one in the book, aspirin.

A salicylate.

It's been around since Bayer first marketed it in 1899.

It is a true workhorse.

It has four distinct properties.

Analgesic for pain, antipyretic for fever, anti -inflammatory, and antiplatelet.

That antiplatelet effect is why my dad takes a baby aspirin every day, right?

Exactly.

At low doses, it makes the platelets slippery.

It prevents them from clumping together, which is what causes clots that can lead to transient ischemic attacks, TIAs, and heart attacks, MIs.

It's excellent for cardiovascular health in that regard.

But there is a massive flashing red light in the text regarding aspirin.

A safety alert.

If you take nothing else away from this section, listen to this.

This is the Reyes syndrome warning.

You must never give aspirin to children or adolescents who have viral symptoms, the flu, chicken pox, any kind of virus.

Never.

Why?

What happens?

It is linked to Reyes syndrome, which causes acute swelling of the brain,

encephalopathy, and liver damage.

It is a devastating condition.

It can be fatal or cause permanent brain damage.

It's just not worth the risk.

So a kid with a fever?

Acetaminophen.

Full stop.

Never aspirin.

What does aspirin toxicity look like in an adult?

If a patient takes too much, what are the classic signs?

The number one sign the book points to is tinnitus, ringing in the ears.

If your patient on high -dose aspirin for arthritis says their ears are ringing, you stop the drug.

That is toxicity speaking.

Okay, tinnitus.

You also see vertigo, dizziness, and in some people bronchospasm.

Bronchospasm, like an asthma attack.

Yes, in patients who have a hypersensitivity.

And the text has a fascinating little note that these patients should also avoid foods that are rich in salicylates.

Wait, salicylates are in food?

Yes.

The book lists prunes, licorice, raisins, and some spices.

It's a weird list, but if you have a patient who is hypersensitive to aspirin, they need to know this diet information.

Okay, moving to the drug that is in everyone's medicine cabinet, but is probably the most misunderstood drug on the list.

Acetaminophen, brand name Tylenol.

The prototype.

Now, I need you to lean in because this is a major point of confusion.

Acetaminophen is an analgesic and an antipyretic.

It is not an NSAA.

I feel like we need a sound effect for that.

It is not an NSAA.

Say it again.

It does not have significant anti -inflammatory properties.

It weakly inhibits prostaglandin synthesis, which helps with aches and fever.

But if you have a massive swollen red inflamed knee,

acetaminophen isn't going to fix the swelling.

It might help the pain a little, but the inflammation will stay.

So why do we use it so much?

Because it's gentle on the stomach.

It doesn't inhibit COX -1 in the gut.

It doesn't cause ulcers.

And crucially, it doesn't interfere with platelets.

It has a different safety profile.

So for dysmenorrhea, those menstrual cramps, it's a good choice if you are worried about heavy bleeding because it won't make it worse.

Right.

But acetaminophen has a huge Achilles heel, and that is the liver.

This is the dosage math we all have to memorize for the exam.

You have to know this.

Acetaminophen is metabolized by the liver.

If you take too much, you overwhelm the liver's ability to process it, and you create a toxic metabolite that actively destroys liver cells.

So what's the limit?

The maximum dose for a healthy adult is 4 grams per day.

That's 4 ,000 milligrams.

But the text tightens that rule for frequent users, right?

It does.

If someone takes it every single day for something like chronic arthritis, the recommendation drops to 2 grams or 2 ,000 milligrams per day to preserve the liver over the long term.

What happens in an overdose?

What does it look like?

It's scary because it's insidious.

The end result is hepatic necrosis, liver death.

And it's a slow, ugly process that happens over one to four days.

The early signs are just nausea, vomiting, diarrhea, abdominal pain.

It looks like the flu.

It looks just like the flu.

But inside, the liver is failing.

Is there a rescue drug, an antidote?

Yes.

A cetal cysteine.

The brand name is Eukomist.

It works by chemically converting those toxic metabolites into nontoxic ones.

It saves the liver, but you have to give it early before the damage is done.

And we monitor the LFTs, the liver function tests.

Absolutely.

AST, ALT, ALP, bilirubin.

You're watching those numbers climb.

And one more huge teaching point for your patients.

Read the labels on over -the -counter drugs.

Acetaminophen is hidden in everything.

Cold medicine, flu medicine, sleep aids.

Oh, right.

If you take Tylenol for headache and then NyQuil for a cold, you might be doubling up and blowing past that 4 -gram limit without even knowing it.

That is how so many accidental overdoses happen.

And obviously, avoid alcohol.

Avoid alcohol.

It puts an extra strain on the liver, which is already working overtime.

Scary stuff.

Okay, let's shift gears.

We are moving from the over -the -counter aisle to the locked cabinet.

Section 3, opioid analgesics for moderate to severe pain.

Now we are dealing with the Controlled Substances Act of 1970.

These drugs are classified by their potential for misuse.

So how do they work?

What's the mechanism?

They work primarily by activating MU receptors in the CNS.

When you turn the key in a MU receptor, you get analgesia, which is great.

That's the pain relief.

But you also get respiratory depression, euphoria, and sedation.

It's a package deal.

You can't really separate the pain relief from the breathing issues entirely with these drugs.

For the most part, no.

There are also capper receptors, which the text mentions.

Cap activation gives you analgesia and sedation

without the respiratory depression or euphoria.

But most of our big guns, morphine, hydromorphone, are primarily MU agonists.

Let's talk about the side effects.

The text lists the greatest hits of opioid problems.

Yes.

Nausea and vomiting, very common, especially at first, but usually wears off.

Urinary retention, especially in older men with prostate issues.

Orthostatic hypotension, they stand up and get dizzy because their blood pressure drops.

Right, a huge fall risk.

A huge fall risk.

But the one that never goes away, the one you have to be proactive about, is constipation.

Why constipation?

What's the mechanism there?

Opioids have MU receptors in the gut.

And when they're activated, they slow down peristalsis.

They basically put the gut to sleep.

The stool sits there, it gets harder and drier.

If a patient is on opioids, they need to be on a bowel regimen, period.

You can't wait for them to get constipated.

You have to prevent it.

Stool softeners, maybe a stimulant laxative, fluids, fiber, you have to be aggressive.

Let's look at the king,

the prototype, morphine sulfate.

Derived from the sap of the opium poppy, it is the gold standard.

Every other opioid is measured against it.

Is it stronger than morphine?

Weaker than morphine?

What are the main uses listed in the text?

Acute pain, obviously.

Myocardial infarction, a heart attack.

It relieves the pain and the anxiety, which actually lowers the workload on the heart.

It's cardioprotective in that way.

Interesting.

Cancer pain, of course.

And one that might surprise you.

Dyspnea from pulmonary edema.

It helps with that sensation of air hunger.

Pharmacokinetics.

How does it move through the body?

If you give it orally, you have to deal with the first pass effect.

The liver gets the first crack at it and chews up a huge amount of the drug before it ever reaches the bloodstream.

So oral doses have to be much higher than IV doses to get the same effect.

And 5E is fast.

5E is very rapid.

Yeah.

On set in 5 to 10 minutes.

But it doesn't last long.

What's the half life?

The text says 2 to 4 hours.

It's short.

You have to re -dose frequently to stay on top of the pain.

Let's drill down on the big killer.

Respiratory depression.

This is what keeps nurses awake at night.

It should.

This is the most serious adverse effect.

The text gives a heart number.

Monitor respirations.

If the respiratory rate falls below 10 breaths per minute, that is respiratory distress.

Less than 10.

Got it.

You hold the dose,

you stimulate the patient, and you get ready with the antidote.

What else should we be looking for?

Look at the pupils.

Meiosis pinpoint pupils is a classic sign of toxicity.

And check the bladder.

Palpate it.

Monitor urine output to ensure it's greater than 600 milliliters per day because that urinary retention is real.

Now, here is a piece of clinical reasoning the text offers regarding head injuries.

Why is morphine contraindicated in a patient with a head injury?

This is such a great test question because it connects two systems.

It's fascinating physiology.

Opioids decrease respiration.

When you breathe less, you don't blow off as much carbon dioxide, so you retain CO2.

High CO2 in the blood is a potent vasodilator.

It makes the blood vessels in the brain expand.

And if your brain is already swollen from an injury.

Expanding the blood vessels inside a closed box, the skull increases intracranial pressure or ICP even more.

It's incredibly dangerous.

You mask the neurological signs and you actively worsen the pressure.

So you have to be extremely cautious with opioids and head trauma.

That is a crucial why.

So by that same logic, asthma patients are also a risk.

Yes, because their respiratory reserve is already compromised.

You don't want to suppress the drive to breathe in someone who's already struggling to breathe.

Let's apply the nursing process here.

You have an order for morphine of faith.

What do you do before you even think about pushing that plunger?

Assess.

Get a full set of baseline vitals, especially respirations and blood pressure.

Check their pupil size and get a drug history.

Do they just take a Valium or drink three beers before coming in?

Because alcohol and sedatives will compound the respiratory depression.

And when you give it.

Before the pain peaks.

The text is clear on this.

It is much harder to chase pain once it's out of control than to stay ahead of it.

And safety put the side rails up.

They will get dizzy from the orthostatic hypotension.

It's a fall risk.

And always have the antinode ready.

Have naloxone available.

Always.

Morphine is the standard, but we use a lot of synthetics now.

Let's talk about Mapparadine.

Mapparadine.

The brand name is Demeril.

It has a shorter duration of action than morphine.

And one weird quirk, the book notes.

It does not suppress the cough reflex like morphine does.

It has no antithesis of property.

Why was it so popular historically?

It used to be everywhere.

It was the go -to drug for labor and delivery for a long time.

The text explains that it causes less respiratory depression in the newborn than morphine does.

It also causes a bit less constipation.

But it has largely fallen out of favor.

Why?

What's the big problem with Mapparadine?

The metabolite.

Yeah.

This is the danger.

Mapparadine breaks down in the body into a toxic substance called Normaparadine.

This stuff accumulates and causes neurotoxicity.

What does that look like?

Nervousness, tremors, agitation, and eventually seizures.

So if I have an older adult with kidney issues.

Absolutely not.

They can't clear the metabolite.

The text is very specific.

Avoid in older adults, avoid in patients with advanced cancer, and do not use for more than 48 hours.

It is not for chronic pain.

If you see an order for long -term Demerol, that is a huge red flag that requires a call to the provider.

OK.

What about hydromorphone?

Deloaded.

We see this everywhere now.

Hydromorphone is a semi -synthetic opioid.

Here is the math you must know for your exam and for your life as a nurse.

It is approximately six times more potent than morphine.

Six times.

So if I have a patient who is used to getting six milligrams of morphine, and I give them six milligrams of deloaded by mistake.

You just gave them the equivalent of 36 milligrams of morphine.

You could easily stop their breathing.

You have to respect the potency.

It's not a one -to -one conversion.

So why use it if it's so much more potent?

The text mentions it has fewer hypnotic or sleepy effects and less GI distress than morphine.

For some patients, it's a cleaner drug with fewer side effects.

But when you give it IV, you must dilute it with saline and push it slowly over two to three minutes.

Do not slam it in.

Okay, moving to section six.

We see combination drugs a lot.

Vicodin, Percocet.

Why do we mix them?

It's about synergy.

You combine an NSAID like ibuprofen or acetaminophen with an opioid like hydrocodone or oxycodone.

The NSAID attacks the pain peripherally at the site of the injury.

The opioid attacks it centrally in the brain.

So you're hitting them in two different directions.

Right.

And by attacking on two fronts, you can use a smaller dose of the opioid to achieve the same level of pain relief.

And a smaller dose of the opioid means less respiratory depression, less sedation, and less addiction risk.

Exactly.

It's a dose -sparing effect.

Let's talk about the machine that beeps in the night.

The PCA, patient -controlled analgesia.

This is a pump that allows the patient to self -administer small ID doses,

usually morphine, fentanyl, or hydromorphone, by pushing a button.

Patients love this sense of control.

But is it safe?

Can't they just mash the button over and over and overdose?

No.

There's a built -in safety feature called a lockout mechanism.

The provider programs it.

It might be set to something like you can have one milligram every 10 minutes.

If the patient pushes the button five times those 10 minutes, they still only get one dose.

The machine locks them out.

But there is a huge golden safety rule here, and it usually involves well -meaning families.

The PCA by proxy problem.

This is a nightmare scenario.

The rule is, only the patient pushes the button.

Not the wife, not the mom, and definitely not the nurse.

Why?

What's the reasoning behind that?

Because sedation is the very first sign of impending overdose.

If the patient is too sleepy to push the button, they don't need the drug.

That is a natural safety mechanism.

If grandma comes in and pushes the button while the patient is asleep because she doesn't want him to wake up in pain, she overrides that natural safety check and can stop his breathing.

That's a powerful way to put it.

What about transdermal patches?

Fentanyl patches?

These are designed for continuous around -the -clock pain control.

So this is for chronic pain,

cancer pain.

They are not for acute pain or post -op pain.

Why not?

Because they take hours to start working.

You can't titrate them quickly if the pain changes.

And fentanyl is incredibly potent, much more so than morphine.

The text specifically warns, use caution in patients weighing less than 110 pounds.

They might not have the body mass to handle the dose safely.

Let's look at special populations.

Children first.

How do you assess pain in a three -year -old who can't talk very well?

It's incredibly difficult.

They can't describe throbbing or burning.

The text says we have to use age -appropriate tools.

It highlights things like the Outscale or the Juan Baker Faces Scale.

Oh, the one with the cartoon faces.

Right.

It has faces ranging from a big smile for no hurt to a crying face for hurts worst.

The child can just point to the face that shows how they feel.

And an administration.

Liquid medications are best.

And be honest.

The text warns against telling a kid a needle won't hurt.

You can use pictures to explain what's going to happen.

Okay, older adults.

We know their physiology changes dramatically.

Their liver and renal function decline.

They don't metabolize or excrete drugs as quickly as a younger person.

So the drugs accumulate and the half -life gets longer.

The mantra is start low, go slow, start with the lowest possible dose and titrate up very carefully.

There are also belief barriers with older adults that the text mentions.

Yes.

They often under -report pain.

They don't want to be a burden to the nursing staff.

Or they grew up in an era where drug addict was a huge stigma, so they fear taking even one pill because they don't want to get hooked.

And what if they have dementia and can't report pain at all?

You have to become a detective.

You have to look for physical signs.

Moans, grimacing clenched teeth, restlessness, pacing, aggression.

That behavior might be their way of saying, I hurt.

Cancer patients, the text makes it clear this is a different ballgame.

It is.

For cancer pain, we follow the WHO, the World Health Organization, ladder.

Step one, non -opioids.

If that fails, step two, mild opioids.

If that fails, step three, strong opioids like morphine.

Is there a maximum dose for cancer patients on morphine?

No.

And this is a really important concept.

For cancer pain, there are no set dosage limits.

You titrate upward until pain relief is achieved or the side effects become intolerable.

If they need massive doses due to tolerance from long -term use, you give massive doses.

The goal is comfort.

What about patients with a history of substance use disorder?

This is a really tricky area, ethically and clinically.

Do we deny them pain meds after surgery?

No.

The text is very clear.

Pain is pain.

They have a right to relief.

Opioids are safe and effective for them, though they may require larger doses due to their pre -existing tolerance.

But, and this is a key warning, you have to avoid a specific class of drugs in these patients.

Which class?

The agonist antagonists.

Why?

Because those drugs can actually rip the opioids they're dependent on off the receptors and throw the patient into immediate, violent withdrawal.

Which leads us perfectly into section seven, adjuvants and agonist antagonists.

Let's start with adjuvants.

What is an adjuvant?

Adjuvants are helper drugs.

They were developed for other purposes, like treating seizures or depression.

But we found out they're really good at treating specific types of pain, especially that neuropathic nerve -based pain.

What are some examples from the book?

Anti -convulsants like gabapentin, brand name Neurontin, tricyclic antidepressants like amitriptyline, corticosteroids to reduce inflammation around nerves,

even local anesthetics like a lidocaine patch.

And the benefit here is - They spare the opioids.

If the gabapentin is handling the burning nerve pain, you might need less morphine for the underlying tissue pain.

That makes the whole regimen safer and reduces side effects.

Okay, now let's untack this opioid agonist antagonist category.

It sounds like a contradiction.

It is a chemical compromise.

These drugs, the prototype is Nalbufenbine to some opioid receptors to give pain relief.

That's the agonist part.

But they block other receptors.

That's the antagonist part.

Why would we do that?

What's the point?

To decrease the potential for abuse.

They are designed to cause less euphoria than a pure agonist like morphine.

They're often used in labor because they provide pain relief with less risk to the baby's breathing.

But there's a big warning.

A huge warning.

The text says never give these to cancer patients who are on high -dose pure opioids because the high doses needed would lead to CNS toxicity.

And again, as we just said, never give them to someone who is physically dependent on pure opioids.

The antagonist part of the drug will kick the pure opioid off the receptor.

And you will precipitate withdrawal.

Instantly.

They will have abdominal cramps, nausea, sweating, tremors, and they will not be happy with you.

Okay.

Section 8.

The antidotes.

The safety net.

Naloxone.

Brand name Narcan.

Naloxone is a pure opioid antagonist.

It has a higher affinity or attraction for the opioid receptor than the opioids do.

It's like a bully.

It shoves the morphine out of the way, sits on the receptor, and locks the door.

And it reverses the respiratory depression.

Instantly.

It's dramatic.

The person can go from unconscious and not breathing to awake and talking in seconds.

It also reverses the analgesia.

But there's a catch.

And the book calls it the rebound.

What is that?

Naloxone has a very short half -life, maybe 30 to 45 minutes.

But a drug like morphine might last for four hours.

So you give Naloxone, the patient wakes up, you think, great, crisis averted, and you walk away.

But 45 minutes later, the Naloxone wears off and is metabolized.

The morphine is still floating around in their system, and it relatches onto those now empty receptors.

And the patient stops breathing again.

Correct.

You cannot just give a dose of Narcan and leave.

You have to monitor that patient continuously.

They often need a second or third dose or even a continuous infusion until the opioid is cleared from their system.

And what happens to the patient physically when you slam them with Naloxone?

It can't be pleasant.

It's not pleasant at all.

You're ripping away all their pain relief in an instant.

The text lists the symptoms of reversal.

Tachycardia, nausea, vomiting, sweating, hypertension.

They wake up in excruciating pain.

It's a violent wake -up call.

But it beats being dead.

No kidding.

Okay, finally, section nine.

Headaches, specifically migraine and cluster headaches.

Migraines are classified as vascular headaches.

The classic signs are unilateral, one -sided throbbing pain, often with nausea and photophobia, which is sensitivity to light.

They can last for four to 24 hours.

Who gets them?

What are the demographics?

The text says about two -thirds are females, usually in their 20s and 30s.

And the pathophysiology.

What's happening in the brain?

It's thought to be a neuronal hyper -excitability in the cerebral cortex.

It's like an electrical storm that then causes inflammation and vasodilation of the blood vessels.

The book lists common triggers, too.

The famous ones.

Cheese, chocolate, red wine foods with tiramine, also MSG, stress, weather changes.

And cluster headaches.

How are they different?

These are nasty.

The book describes them as severe, unilateral, non -throbbing pain, usually located right around the eye.

They occur in clusters.

You might get attacks every day for weeks, and then they're gone for months.

No aura, no nausea, and they're more common in males.

So how do we treat migraines?

There are two approaches.

Preventive therapy for people who get them frequently.

That includes beta blockers, like propranolol, or anticonvulsants, like valproic acid.

Then there's treatment for an acute attack.

What do we use for an attack?

For mild cases, aspirin, acetaminophen, or NSAIDS, maybe with some caffeine.

But for moderate to severe attacks, the go -to class of drugs is the triptans.

The prototype in the book is Sumitriptan.

How does it work?

Remember, we said migraines involve dilated, swollen blood vessels in the brain.

Sumitriptan is a serotonin receptor agonist that causes vasoconstriction of the cranial arteries.

It squeezes those vessels back down to their normal size.

Which brings up a major contraindication.

If it squeezes brain arteries.

It can squeeze coronary arteries, too.

So the text is very clear.

Sumitriptan is contraindicated in patients with coronary artery disease, CAD, or uncontrolled hypertension.

You don't want to cure a headache by causing a heart attack.

Wow,

we have covered a massive amount of ground.

From the genetics of pain thresholds all the way to the rebound effect of Narcan.

It is a huge topic because it's the most common symptom we treat.

It's fundamental to nursing.

Let's just do a quick recap.

The big takeaways for the listener getting ready for their exam.

Okay, rapid fire.

One, pain is subjective.

Believe your patient's report.

Two,

acetaminophen is not an NSAID.

Watch the liver.

Know the four gram limit.

Three, opioids require vigilance.

Watch the respirations.

Less than 10 is the danger zone.

Got it.

Four, respect the potency differences.

Hydromorphone is not morphine.

It's six times stronger.

And five, don't let the naloxone wear off before the opioid does.

Monitor, monitor, monitor.

Before we sign off, I want to circle back to that idea you brought up at the very beginning.

Undertreatment.

The text mentioned it explicitly.

It's the final provocative thought, really.

We know the physiology.

We have the drugs.

We know the doses.

The only thing standing between a patient and relief is often the nurse's judgment.

So the question for you is, in a busy clinical setting, when you are tired and the patient is maybe difficult,

will you be the one to stop and assess that fifth vital sign accurately?

Or will you let your own bias, your own exhaustion, keep that gate closed on their suffering?

The text makes it clear.

Pain is subjective.

But your response as a nurse must be objective, knowledgeable, and above all, safe.

Absolutely.

That's the job.

Thank you for diving deep with us today.

To all the nursing students out there studying for that pharmacology exam, good luck.

You've got this.

Thank you from the Last Minute Lecture Team.