How do you do, fellow chemists? It is I, Cute Science Girl, here to talk to you about the molecules and the atoms. My favorite chemistry is when the element combines with the other element to make… another element? A rock? Some plants or something?
Folks, I have a confession to make. I know nothing about chemistry. In fact, that last paragraph was entirely a lie. I am neither cute nor a girl, and I sure don’t know much about science. I am merely a sad, tired nursing student staying up way later than he should be on the eve of a pharmacology test.
Some of you guys may know me as Finn from June’s other (rarely updated) blog, Time For a Misadventure. She’s been asking me for a while now to share some of the stuff I’ve been learning in my classes on this blog, and with a big test coming up I figured it’d be a great time to start! I’m not nearly as good as a writer as June, but I hope that someone finds a bit of this interesting!
With all that said, let’s get cracking!
Things to Know About Pharmacology
Before I can really start talking about various drugs and stuff, there’s a couple things that you should know about me and pharmacology. I’ve compiled a nice bulleted list for you guys:
- I’m really bad at it.
- I’m not a health care professional. Yet.
- I’ll probably be using some fancy-shmancy medical terminology here. If you don’t know what it means, that’s okay – I probably don’t either. I’ll try and explain it in simple terms for both of our sake.
- Did I mention I’m kind of bad at it?
With that out of the way, it’s time to talk about some simple terms!
To kick things of, it’s important to understand how a medication works and is processed by the body. The absorption of a drug is, to put it simply, the process of getting the drug from wherever it’s been administered to the bloodstream. Medication can be administered by kinds of different routes. The most common ones are by mouth (abbreviated as PO), as an injection into your muscles (IM), as an injection into your subcutaneous tissues (SubQ), and directly into your veins by way of an IV (oddly enough, abbreviated as IV). Of these, the slowest route for administration is the mouth, and the fastest is by an IV.
The next step in the drug process is distribution. Distribution is the transportation of a drug from the blood stream to the place it needs to go. The medication does this by binding to transport proteins and hitching a ride throughout the body. The most common protein used for this process is albumin.
It’s important to note two things regarding transportation. Firstly, very few drugs can reach the brain. The blood-brain barrier acts as a filter, only allowing very small particles past. On the other end of the spectrum, almost all drugs can pass through the placental barrier. This is why so many medications aren’t supposed to be taken by pregnant women. It’s best to assume that if mamma is taking a drug, baby’s taking it too, for better or worse.
Now, back to the drug process. The next link in the chain is metabolism. This is how a medication is converted from it’s pharmacologically active form into something more water soluble and easily excreted. Mostly likely, this is going to be done by your liver. When a drug is metabolized (I.e, broken down), it forms pieces called metabolites.
Lastly, the drug is excreted from your body, most likely by the kidneys (urine). Though the kidneys are the primary organ for excretion, others also can take part in the process. Some drugs are excreted by the lungs when you exhale. Some are excreted by your skin when you sweat. A lot of drugs are excreted in breast milk, which is yet another reason why pregnant or nursing mothers can’t take many different medications. By now, I bet you’re sick of the word excreted
Moving on, let’s talk about something exciting – controlled substances! There are 5 categories for controlled substances, called “Schedules.” The lower the schedule, the more likely a drug is to be abused, and vice versa. I like bulleted lists a lot, so here is another one for you guys:
- Schedule 1: Drugs that are easily abused that have no medical benefit. Ex: Ecstasy
- Schedule 2: Drugs that are easily abused, but have specific medical use. Ex: Adderal
- Schedule 3: Drugs that are less likely to be abused, but can lead to physiological and psychological dependence. Ex: Steroids
- Schedule 4: Low abuse potential, and have accepted medical use. Ex: Lorazepam
- Schedule 5: Very low abuse potential. Ex: Lomotil
In the hospital setting, controlled substances are a bit of a nuisance. Every time you draw up a controlled substance, you have to count all the medication in the drawer and report how much is left. At the end of the night, every single controlled substance is counted. If there is a discrepancy between how many meds are actually present and how many the computer says are supposed to be present, then everyone gets drug tested.
And no one goes home until the tests are finished. This takes a long time. After a 12 hour shift, absolutely no one wants to deal with several additional hours sitting in the hospital keeping them away from a warm bed. Needless to say, nurses are very, very careful with controlled substances. Or at least they’re suppoooosed to be, but that’s another blog post entirely!
The next thing I want to talk about is pregnancy categories. Much like controlled substance schedules, a drug can fall into 5 different categories depending on its effect on pregnant women. Time for another bulleted list, folks.
- Category A: The drug is safe. Animal and human drug trials have shown no risk towards the fetus.
- Category B: While animal trials have shown no risks to the fetus, there hasn’t been any trials on its effect on humans.
- Category C: Animal trials of the medication have shown evidence of risk to the fetus, but again, no trials on its effects on humans. The benefits the drug may have on the mother must be weighed against the risk it has hurting the fetus. Most drugs fall under this category.
- Category D: There is an evidence of risk to the fetus when taking this medication. Again, the benefits this drug may have on the mother must be weighed against the risk it has on hurting the fetus.
- Category X: A drug so dangerous, the medical professionals skipped forward 16 letters to appropriately name it. With Category X drugs, the benefit the drug may have on the mother never outweighs the risk it has on the fetus.
A Category X drug would have what we call a Black Box Warning (BBW) for use in pregnant women. With a black box warning, the FDA has deemed that a drug has a high risk for causing death in specific populations or situations. While a medication may be completely harmless to one person, it could kill someone else. For example, the drug levothyroxine has a FDA mandated black box warning for usage as a means of treating obesity. While levothyroxine does an exceptional job at boosting your metabolism, if you take it for weight loss while you have a fully functional thyroid gland you’re going to have a bad time.
Now I want to talk about a drug’s half life. This is the amount of time it takes for a drugs concentration in the body to decrease in half. Simple enough, right?
Well here’s the tricky part regarding half life. Let’s say you administered 40mg of a drug that has a half life of 12 hours. That means that 12 hours after administration, half of it should have left the body, leaving 20mg. Now, let’s jump forward another 12 hours. The drug should be completely eliminated from the body, right? If only it were that simple! In reality, the concentration of the drug would be at 10mg. Fast forward another 12 hours, and it would be at 5mg, another 12, and it’s 2.5mg, and so on.
See what’s happening? Every 12 hours, the drug’s concentration in the body is halving. Thus is the problem with half life: It takes an unbelievably long time for a drug to leave the body. If you want to determine how long it will take for a medication to leave the body, the down and dirty way to do it is to multiply the drug’s half live by 3. This might not seem too bad for medications that half a short half life, but what if a drug has a half life of 30 days? You’re going to be waiting a long time for that medication to leave the body.
Lastly, I got a pop quiz for you guys: What’s the difference between the two drugs Tylenol and Acetaminophen? Just take a guess. Here’s the correct answer: they’re exactly the same thing!
In the pharmacy world, ever drug has a Trade Name, aka the brand name, and a Pharmacological Name, aka the generic name. In order for a generic drug to be sold, the Federal Drug Administration has to approve it. In order for it to be approved, it has to be exactly the same (or more technically worded, biologically equivalent) as the name brand.
Now when it comes to herbal drugs, the sky’s the limit. While there is an organization out there that can approve an herbal medication as having the same therauputic effect as a similar drug, it’s not required by any means.
So next time you go to the drug store and plan on picking up some headache medication, feel free to save a couple bucks and get the generic instead! And if you’d rather take some herbal medications, make sure you read the whole label!
And that’s the basics! Whew. That’s a lot of information, isn’t it? Well buckle up, buttercup: We haven’t even begun. Trust me. I’m already crying. I recommend some coffee.
Pain and Inflammation: Concepts
“Four pages in and it’s finally time to start talking about some medications!” …Is what I’d like to say, but before we can talk about pain meds, we gotta talk about the concepts of pain and inflammation for a bit. I know, it’s a bummer, but bear with me. This stuff is important!
Firstly, we need to find a good definition of pain.According to the International Association of the Study of Pain, pain is defined as follows:
“Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.”
That sounds all well in good, but us here in the Nursing field have another definition of pain that’s a bit easier to put into words:
“Pain is whatever the patient says it is.”
In a nursing-patient relationship, the expert on pain isn’t the doctor, it isn’t the nurse, and it isn’t the pain association. It’s the patient. If I were to come into the hospital complaining about how my pharmacology class is causing me severe pain (which it is, emotionally and physically), the staff may roll their eyes a bit, but they’d believe me. Pain is such a subjective thing that it is nearly impossible to tell if someone is or is not experiencing it.
The management of a client’s pain depends on several factors, such as the nature of the pain, the location of the pain, the severity of the pain, and whether or not the pain is radiating throughout the body. Pain can be managed through non-pharmacological means such as physical therapy, behavioral changes, acupuncture, or even electric shocks. If necessary, pharmacological interventions, called analgesics, may be needed.In severe cases, surgical treatment may be required.
It is important to note that it is best to take pain medications when the pain is relatively minor . It is significantly easier to treat pain before it gets bad.
Everyone experiences pain differently. An individual’s pain threshold is the level of stimulus needed for them to produce the perception of pain. This can very wildly from person to person. What I think is painful is not the same as what June thinks is painful. What June thinks is painful is not the same as what Joe Shmoe on the street thinks is painful.
Closely related is an individual’s pain tolerance. This is the amount of pain they can endure before it begins to impact their daily life. Again, this is dependent on the person. While I may think that pain rated 3 on a scale of 1 to 10 is absolutely unbearable, June may rate her pain as a 8 and not even feel bothered by it.
Breakthrough pain is a form of pain that occurs even when you’re taking scheduled pain medications. It usually occurs in patients who are experience chronic pain.
With pain medication comes the problem of medication tolerance. Gradually, as you take pain medication, your body grows more tolerant of the medication, and higher doses need to be administered to get the same effect. This isn’t really a bad thing or a good thing, it just means the nurse needs to recognize the need for more medication.
A common fear that patients have when they’re taking pain medication is dependence. Now, there are two types of dependence: Physical and physiological dependence. With physical dependence, your body has adapted to the presence of a drug and depends on its effect to function. If you were to suddenly take them off of their pain meds, they would go through severe withdrawal. Physiological dependence is compulsive drug use not due to pain relieving effect, but the high it gives you. This is what many people refer to when they express fears of gaining an addiction to pain meds.
Contrary to popular belief, addiction to pain medications is rare if it is being taken as it was intended. If you’re in pain and need the medication to function, you’re not addicted to it. You’re just in pain.
Now, let’s talk about some physiology!
When your body receives an injury, a chemical called prostoglandin is formed. Prostoglandin assists in regulating many different bodily functions, but are primarily used in the body’s inflammatory response. COX enzymes assist in the formation of prostoglandin, and are generally divided into two creatively named categories:
- COX1: Enzymes that have a protective effect on the kidneys and stomach. If these enzymes are inhibited, an individual will experience gastric irritation, ulcers, and bleeding.
- COX2: Enzymes that cause pain and inflammation. Inhibiting these enzymes reliefs pain and inflammation.
Most drugs work by inhibiting both of these enzymes, causing analgesia (pain relief) and decreased inflammation as well as gastric irritation. However, there are some that can selectively inhibit COX2 and avoid inhibiting the protective effects of COX1. Regardless, long term use of medication that inhibit either enzyme may result in gastrointestinal problems.
Now, let’s talk about some specific disease processes. Ever hear of something called gout? I’m sure many of you are familiar with it, or may be experiencing it yourself.
Gout is a condition in which uric acid builds up into your joints, and eventually ends up crystallizing. This causes an inflammatory response because believe it or not, your body doesn’t particularly care much for crystals being in its joints. Gout is extremely painful, and occurs rapidly. For some reason, it occurs most frequently in the big toe.
Treatment for gout is generally just using medications or special diets to control your body’s levels of uric acid. The best way to decrease your risk for developing gout, avoid eating excess amounts of red meat, sea food, and alcohol. I know, it sucks, but want to know what else sucks? Crystals. In your joints.
As we reach the home stretch for pain and inflammation concepts, we need to talk about one more thing: Headaches. If I were a guessing man, I’d say that headaches are probably the primary reason you use pain meds.
There are three main types of headaches to consider. The first is a cluster headache. This is a type of headache that takes place on one side of your head. It causes extremely severe pain, and tends to manifest itself with other symptoms on the same side, such as tearing up, ptosis (drooping eye), and stuffy nose.
The next kind of headache, and the most common, are tension type headaches. These cause mild to moderate pain on both sides of the head, and may feel like a tight band has been wrapped around your head.
Lastly, we have the dreaded migraine. Migraines are caused by a multitude of environmental and genetic factors. They start when your intracranial blood vessels start to dilate. Usually they take place on one side of the head with moderate to severe pain. Usually, migraines are accompanied by other symptoms such as nausea, vomiting, photo sensitivity, and sometimes numbness and tingling on one side of the face as well as speech difficulties.
Alright! We did it! We now know enough about pain and inflammation to have some form of understanding regarding how things work. Time to get into the real nitty gritty: The medications.
Pain and Inflammation: Medications
Acetylsalicylic Acid: Or, as most of you probably know it by, aspirin. The primary use for this medication is headache, fever, and myocardial infarction (a fancy word for heart attacks.) It works by decreasing platelet aggregation in your blood, which is a way of saying it makes your blood clot less. It does this by inhibiting prostoglandins
There are two primary adverse effects of acetylsalicylic acid. The first is that since your blood clots less, you bleed a lot more. The second is nephrotoxicity, otherwise known as poisoning your kidneys. You’ll see this one a lot so keep it in mind.
Toxicity is a serious concern when taking aspirin. Considering a large amount of people take aspirin for everything, it’s easy to accumulate a lot of it in your system. In children, any more than 4g of this stuff taken in one day is enough for them to experience an overdose. For adults, it takes more than 20-25g. Symptoms of acetylsalicylic acid toxicity are seizures, tetany (muscle spasms), tinnitus (ringing in the ears), and dizziness. Acetylsalicylic acid toxicity is called salicylism.
Aspirin interacts with a number of drugs. When taken with NSAIDs (Non Steroidal Anti Inflammatory Drugs), bleeding risk is increased and the NSAIDs effect is decreased. When taken with Anti-coagulation drugs, bleeding is increased. Alcohol increases the risk for toxicity. When taken with insulin, blood sugar is decreased.
Lastly, aspirin has a Black Box Warning for children under the age of 6 due to a risk for swelling of the brain, a condition called Reye’s Syndrome.
Acetaminophen: Bet you’ve all heard of this guy before. Acetaminophen is used for pain and fever, but has no anti-inflammatory effect. Like aspirin, it works by inhibiting prostoglandins.
Again, like aspirin, taking acetaminophen is nephrotoxic. It is also hepatoxic, which means poisoning of the liver. This is another side effect you’ll see frequently because so, so many drugs are metabolized in the liver.
Acetaminophen is the absolute safest pain medication for children and pregnant women. Because of this, it is in everything. That means like aspirin, it’s really easy to overdose. The max daily dosage is 4g.
You know how everyone says not to take medications with alcohol? Yeah. There’s a reason for that, and it’s not because it boosts the effectiveness of the drug. Alcohol is very damaging to the liver. If you take a medication like acetaminophen or aspirin with alcohol, it has an additive effect and your lever is damaged even more. You like your liver? Don’t take medications with alcohol!
The other noteworthy drug interaction acetaminophen has is that it increases the effect of seizure medications.
And that’s about all there is to say about acetaminophen. All in all, a solid drug.
Ibuprofen: We’re on a roll here with familiar medications, aren’t we? Ibuprofen is used for fever, pain, and dysmonorrhea (menstrual cramps). In high doses, it also has an anti-inflammatory effect. Ibuprofen is one of those drugs I mentioned earlier that inhibits both COX1 and COX2. Can you guess what that means?
I’m assuming you guessed “Gastrointestinal upset is a side effect”, because I believe you’re a smart individual.Because of that, it is recommended to take ibuprofen with food. It is also nephrotoxic, and has a risk for gastrointestinal bleeding.
Ibuprofen is absolutely 100% NOT safe for pregnant women! It can cause a condition called Patent Ductus Arteriosus. The ductus arteriousus is an opening between two major blood vessels that bypass the baby’s lungs when it is still in the womb. If it is born and the vessel is still patent, a term meaning open, the baby’s blood will not get properly oxygenated because the blood is going around the lungs. Please don’t take ibuprofen if you’re pregnant!
Ibuprofen also has a Black Box Warning for use for treatment of perioperative pain after a coronary artery bypass surgery. Which is super specific, but this is the way of black box warnings.
Like the other drugs mentioned, ibuprofen has an increased risk for bleeding when taken with other anticoagulants, and alcohol increases the risk for toxicity. See a trend?
Meloxicam: Now we have an anti-inflammatory drug! Meloxicam is a NSAID (remember what that stands for?) and is used for the treatment of osteoarthritis and rheumatoid arthritis.
Side effects for meloxicam are shortness of blood, hemoptysis (coughing blood), and bronchospasms. Because of this, it is not recommended for asthma patients. Additionally, the drug is pregnancy category D.
Meloxicam has a Black Box Warning for cardiovascular events.
This drug boosts the effects of lithium supplements and increases its concentration in the body. Lithium has a very tiny therapeutic range, so there is a high risk of toxicity here. As expected, don’t take it with alcohol.
Endomethacin: Another anti-inflamatory drug. It’s used in for gout attacks as well as rheumatoid and osteoarthritis. This is another drug that works by inhibiting both COX1 and COX2.
Side effects of note with endomethacin are bleeding, and if given via an IV, pulmonary hemorrhage.
Don’t take this drug if you’ve got any gastrointestinal bleeding or have significantly renal impairment
Celexacib: What’s with all the anti-inflammatory medications all the sudden? Like meloxicam and endomethacin, celexacib is for rheumatoid arthritis, osteoarthritis, and this time juvenile arthritis. Unlike those other two meds, however, this one is a selective COX2 inhibitor. That being said, with prolonged use it can still cause gastrointestinal upset.
If you’re allergic to NSAIDs, or ASAs, you shouldn’t take this drug. You also shouldn’t take it if you have any renal impairment.
Celexacib has a Black Box Warning for cardiovascular events, much like meloxicam.
This drug has an 11 hour half life due to it being highly protein bound. Just an interesting little tidbit.
Now let’s talk some gout meds!
Allopurinol: This is the most basic of all gout medications. All it does is decrease the amount of uric acid in the body. It has no analgesic or anti-ineffective effect. It is purely a prophylactic drug, meaning it’s a medication that is taken as a preventative.
It can cause pruritus (itching), rashes, hepatoxicity, and renal toxicity.
When taken with warfarin, risk of bleeding increases. When taken with any ACE inhibitor, it increases the blood pressure lowering effect.
It’s important to increase your fluid consumption when you’re on this medication. Uric acid is excreted through the kidneys, so you need a lot of fluid to increase urine output. A yearly eye exam is also recommended.
Colchicine: In contrast to allopurinol, colchicine is used in acute gout attacks, though it also functions as a surgical gout prophylaxis. It works by inhibiting leukocytes from reaching the injury site, preventing the inflammatory response.
Some side effects for this medication are paralytic illeus, euplastic anemia, bone marrow suppression, and vasoconstriction.
As this medication is for acute gout attacks, it needs to be taken at the first sign of gout to work properly.
Morphine: Moving out of gout meds and back to pain meds, say hello to the big dog himself. Morphine is a pretty crazy drug. As an opioid, it doesnt particularly work by inhibiting any sort of inflammatory effect. Rather, it simply blocks your brain’s perception of pain. It doesn’t fix your pain per say, it just makes you forget it’s there.
Morphine is a central nervous system depressant. That means it knocks you out real good. It can also cause hypotension.
Because it has such a powerful effect on the CNS, you cannot give morphine to a patient who is sedated or suffering from respiratory depression. If you give morphine to a patient who is already breathing very little, it will just make them stop breathing completely.
Don’t take morphine if you have increased cranial pressure or if your pregnant. If the mother gets morphine, the baby gets it too.
It goes without saying, but don’t take this medication with alcohol. Remember what I was saying about respiratory depression? If you take this with alcohol, that can also happen to you. If you like breathing, I recommend staying away from alcohol while on morphine.
Morphine is the drug of choice for chest pain. It decreases the heart’s oxygen demand, decreases the heart’s workload, and causes vasodilation. All of that stuff is very welcome for a troubled heart.
While morphine tends to be the opioid of choice in a lot of situations, there are many others that are used in the hospital setting.
Now! Rapid fire Opiods!
Codeine is used for mild pain relief and as a antitussive (cough suppressor). It has minimal risk of being abused.
Fentanyl is a transdermal pain medication, which means it’s given as a patch. It’s a crazy strong pain reliever, but it takes up to 6 hours for it to be taken into effect. Needless to say, it’s best suited for continuous pain control rather than dealing with acute pain. On the upside, one patch lasts up to 3 days!
Methadone is a cheap, long lasting pain medication that’s given primarily for chronic pain or to those going through withdrawal.
Lortab is a combination med made out of acetaminophen, hydrocodone, and oxycodone. It is the #1 most abused drug in Alabama. If abused, patient can go into severe withdrawal if not properly weaned off.
Lastly, Hydromophone is a pain medication that is given in small doses. It works very well in patients who don’t respond to morphine.
An important drug to consider when administering opioids is Nalaxone. You know how opioids can cause severe respiratory depression? Nalaxone is the drug you give to bring them back. It completely reverses the effect of opioids, raising heart rate, blood pressure, and respiratory rate.
Of course, it also reverses the analgesic effect. During the 1-2 hours this medication’s effect lasts, no further pain meds can be administered. So yes, nalaxone will make the patient breath better, but it’ll also make them hurt. Try to only use it when absolutely necessary.
Finally, let’s talk about some headache mess!
Acetaminophen/Aspirin/Caffeine: This is a combination drug for headache relief. It increases your capillary permeability and causes vasoconstriction. This increases both your heart rate and blood pressure. It’s not recommended for diabetics, as vasoconstriction decreases blood flow.
Sumatriptan: A hardcore headache medication. It provides relief to migraines only. It works by stimulating S-HT1b/d receptors. What’s that mean? Good question folks.
Side effects for sumatriptan include chest pain and coronary artery spasms. Don’t take it if you have any cardiovascular disease, have a history of hypertension, or smoke. In pregnant women, the benefits of the medication outweigh the risks.
SSRI medications increase the effect of sumatriptan. Concurrent use of MAOIs may cause serotonin syndrome.
It’s important to note that Sumatriptan is an abortive therapy. That means that you take it the moment you start feeling a migraine come on.
Ergotamine: Take a deep breath- this will be the last medication we’ll cover. Once again, we’ve got ourselves a headache relief drug here.
It works by affecting the seratonergic, dopaminergic, and alpha adenergic receptors. This medication is given sublingually, which means under the tongue. It also stimulates smooth muscle.
Because of this, it has a Black Box Warning in pregnant women and is a category X drug. It’s not recommended for individuals with cardiovascular disease, children, or renal disease.
Wow. That’s a lot of medications. Enough to make you lose your mind even. I know my brain is fried, and that’s only half of the stuff I have to know for my test!
I debated whacking you guys in the face with some “Infection Medication Knowledge” ™, but considering this is already about 16 pages long, I’ll spare anyone that was crazy enough to read this. Perhaps another time!
And with that, I’m going to sleep y’all. It’s 5am and I gotta leave for class at 7am. Some of you will probably act surprised by this, but those of you in college are probably just rolling your eyes and saying “Pfft. Lightweight.”
Until next time, peace!