Carbamazepine, Trigeminal Neuralgia, Dirty Drug discussed on Real Life Pharmacology - Pharmacology Education for Health Care Professionals


Hey, all thanks for listening. Welcome back to the real life, pharmacology podcast. I'm your host air christianson, pharmacists, and we have got a heavy hitter for a drug today drug called carbamazepine, and there is a ton of clinical pearls with this medication. So we'll just get right into at brand. Name of this medication is tech Raton, and its mechanism isn't totally well understood, and there's multiple possible mechanisms I would say the one that's most commonly associated with the Houston, this drug as binds, sodium channels and alters sodium transfer across cell membranes, which can ultimately slowdown prevent action potentials from happening and synapses and things like that. So kind of a little bit more of a challenging medication as far as the mechanism goes because there is kind of so much ambiguity. And it works in the brain, which makes. Things more difficult to research and understand. But that sodium channel aspect does seem to be important. Other things that, that can potentially cause can stimulate the release of age. So we'll talk about that a little bit adverse effect profile mildly anti corner GIC as well. I would say, in the grand scheme of things that probably isn't a huge, huge deal. But because there are so many different side effects and boxed warnings with this medication now getting into the uses in my clinical practice, probably the three most common, I've seen Tegel tall or carbamazepine used for is seizures BI polar disorder and tread. Jemele neuralgia and it's, it's really a, a messy messy drug as far as lots of drug interactions, which will cover. So that's really why you don't see a lot of provide. Offers using this medication. Because there's so much a monitoring in potential for hazards along the way with this medication. But obviously in a situation like seizures bipolar disorder or trigeminal neuralgia or you know, maybe we're limited options and or it's very serious condition. You may potentially see it. I did want to mention target concentrations, usual. Target concentrations, are four to twelve micrograms per mille. Now with that said in something like epilepsy. This is much more important to find kind of target goal level of, of where we want a patient to be in something like a tragic neuralgia where, you know, you're treating pain and you're treating symptoms. Obviously, it's probably not that big deal to find a target concentrations. Now, if you're recognizing some symptoms of toxic maybe some CNS problems, some GI upset things of that nature. After that might be a situation where you actually check a level. But, you know, in, in try jemele neuralgia for example, ongoing routine monitoring of levels is going to be much, much less important than when you're treating seizures with as medication one thing that always comes up or frequently comes up on exams is carbamazepine is an enzyme inducer, and it can actually auto induce its own metabolism. So kind of stimulates itself stimulates the breakdown of itself until it reaches a steady state, but this auto induction can take weeks maybe in the period of two to five weeks for this auto induction Kana to come to a steady state. So if you've got a patient, that's maybe very stable after, you know, a few days or week or something like that. It. There is potential that those concentrations could come down as kind of this auto induction ramps up a little bit. So what that means if a patient is starting on this medication, and we're doing drug levels and monitoring for efficacy, whether it's reducing seizures, or, you know, mood control by polar disorder we need to have that close monitoring within those, you know, maybe I one to two months that type of thing. Now, adverse affects we've got a boxed warnings with carbamazepine. And so the first one's actually genetic variation. So patients with the. Lille. H L, A B fifteen to, and I have seen that come up on test questions as well. These patients are at risk for severe skin reaction called Steven Johnson syndrome. So that's a good one to remember also warnings on a plastic anemia also a granular Saito, so lots of things to kind of unpack, and you could definitely understand how you don't monitoring certain labs, CBC and things of that nature would be important with this medication. Now talk city at did wanna talk about a little bit. So obviously these box warning things can happen. But in the realm of tax. Cecily due to do to too high of concentrations. I think you can think of it very similarly to, you know, alcohol Fenton, those kind of toxins where you're really gonna have, you know, that CNN's depression, maybe dizziness, maybe a taxi difficulty walking, you know, maybe nausea vomiting, some GI upset confusion things of that nature is what you're going to see if those drug levels get elevated now couple other adverse effects again. I said, this is very dirty drug. I always think about highpoint trivia, I absolutely have seen cases of SIA, D, H and hype. Nate tree Mia from carbamazepine that risk tends to go up as we're on more agents that can also cause highpoint trivia, he think about, you know, loop diuretics or diuretics in general. Also think about SS arise and medications of that nature as well. So definitely important to keep tabs on sodium with this medication liver. Toxicity is possible LSAT's are in with that CBC monitoring as well as sodium monitoring an important aspect that you're gonna wanna follow in a long, you know, with the L F teas that, I mentioned, you got to think about other agents that might be damaging to the liver as well. Obviously in combination with another agent like carbamazepine that can cause some liver problems. That's something to certainly be aware of as you're looking at that patients, maybe poly pharmacy medication list. So with that. Let's take a quick break from our sponsor admitted one one dot com slash stores. Proud sponsor, the real-life pharmacology podcasts, just love the podcast. Enjoy the free material go support met at one one dot com slash store. Tons of resource. You can even get a couple of free ones. If you've never had an audible book, so definitely go, check out those links take advantage of that. If you're pharmacists, or pharmacy student looking for board certification materials. Absolutely. That is a good place to go. Check out what we've got at mid one, one dot com slash store drug interactions. So probably the biggest thing I think of with carbamazepine is it is an inducer and you always gotta remember what an inducer is versus what an inhibitor is. So a sip three four inducer is going to stimulate these enzymes in the liver to clear the body of drug or metabolize drugs. More quickly. So if a drug not carbamazepine is metabolized by CYP three a four and we use carbamazepine. That drug is going to basically be chewed up faster, and it's a facts aren't going to last as long in a patient, who is not on carbamazepine. So it's kind of a simple as simple as I can make explanation to try to understand what happens to these drugs that go through CYP three four and here's some examples, so a picks Aban river rock. Som also warfronts anticoagulant. So if those concentrations fall because we're using carbamazepine that's a pretty big concern. You know, depending upon what you're using it for you're looking at increased risk of DVD p potentially a risk of a stroke. If we don't have adequate anticoagulant, concentrations to help prevent those strokes. So definitely a big deal there, again, gray. Good example, why we try to steer clear from using carbamazepine, if we can avoid it era. Pip Zola lands opinion, a couple of anti psychotics I think of there's anti-hiv drugs. So I think of the protease inhibitors, as well as some, some other oddballs that can be reduced concentrations, and reduce the effectiveness there, alternately, dill, tie them Rapa. Mel again couple of medications you may see amused for hypertension. May see him used for maybe migraine prevention. Maybe atrial fibrillation. A few different uses you can use that type of class for gin, those concentrations could be reduced by adding carbamazepine some of the as all antifungal, you gotta think about contraception. So estrogen contraception could be chewed up a little bit quicker. And that might leave a pair. At more risk for becoming pregnant when maybe they don't necessarily want to be, so that's an important one there as well. Also, some other oddballs hydro Koto and that's got some CYP. Three four metabolic breakdown today. Phil, another example, with the fast food restaurants. Five inhibitors there drug for rectal dysfunction. So very, very important to think about other drugs, whenever carbamazepine I think that's the, the bluntest most simple point. I can can tell you, and I would encourage you, if you see this drug being used to run an interactions check look it up and see what we're going to be affecting. 'cause if you've got a patient on three or four or five, plus medications, and carbamazepine odds are probably pretty favorable that one of might be affected. So very, very important. There. Couple of things I did want to mention, so a grapefruit juice. So that is known to be a sip three or four inhibitor. So this can actually raise concentrations of carbamazepine, so grapefruit, juice with carbamazepine may put a patient at risk for carbonates being toxicity, how important to remember that one. I do wanna I kinda hinted at the teas, you know, thinking about drugs that, that may cause liver function problems, and you add on remains a PM could be potentially an additive effect type of thing. And then I also think of the SAD h which I think I mentioned, a couple of examples there of other drugs that could 'cause that adverse effect, and that low sodium,

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