olanzapine pharmacodynamics (mechanisms/methods of action). What Zyprexa does and how it does it.
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When you read about the mechanism of action, or how it works, in Zyprexa’s PI sheet, it’s almost as vague as how likely it will work. Pretty much every beginning paragraph of the mechanism of action section for every crazy med (and many other non-crazy meds) is a variation on “We don’t know exactly how Panacea, or other drugs like it, works to treat whatever you take it for. In various studies, mostly on rats and other animals, we’ve determined that it does the following…” What you read in the PI sheet is often, but not always the original theorized mechanism of action, or what they thought it does when they started testing the drug for whatever it is now used for1.
After researchers who aren’t being paid by the manufacturer get their hands on med it’s just one study after another, in humans and animals, that supports the original theory. Or determines a precise area in the brain where stuff takes place. Or finds an additional thing the med does. Or finds that it doesn’t do something they originally thought it did. Or finds out that everyone was completely wrong in the first place and the method of action is radically different. That last one does happen. Neurontin (gabapentin) was originally thought to be a synthetic form of GABA that could cross the blood-brain barrier. Turns out that it’s just like every other anticonvulsant and works on voltage channels. Except that it’s unique in that it affects a part of your brain that nothing else touches. Except for Lyrica (pregablin), and a few meds under development (e.g. PD−210714). Still, some people are calling those parts of your brain some people are calling those “gabapentin receptors”, along the lines of benzodiazepine receptors. There supposedly were citalopram receptors as well, but that turned out to be a myth. Ironically gabapentin doesn’t directly affect GABA.
Every day a new peer-reviewed journal is published somewhere adding to our knowledge about how a particular med works, or making us crazier with more contradictory data.
It would be nice if we could break things down into neat parameters like we can with pharmacokinetics, but we can’t. The best we can do is tell you what they originally thought it did, let you know if there are any meds with similar mechanisms / methods (the terms are interchangeable) of action, and give you our best guess as to what it really does based upon more recent research.
2.1 What the PI Sheet Says
as far as we can tell
Another reason why Zyprexa and other meds work, and make you fat, is their effect on the corticotropin-releasing hormone/factor. This particular brain juice affects both your mood and metabolism, and helps to explain why comfort food makes us feel good.
No two medications will have the exact same mechanisms / methods of action. Sometimes a drug that is developed from the active metabolite of another, essentially inert med e.g. Invega (paliperidone) is a predigested form of Risperdal (risperidone) and is basically the same thing. However there is no good conversion of dosages between the two like there is for Tegretol (carbamazepine) and Trileptal (oxacarbazeine). Like Invega and Risperdal, Pristiq (desvenlafaxine) is the active metabolite of Effexor (venlafaxine), but Pristiq has a somewhat different mechanism of action than Effexor. Mainly it kicks Effexor’s ass when it comes to how potent its inhibition of norepinephrine reuptake is.
All SSRIs are essentially interchangeable, making it possible to work out equivalent dosages so you don’t need to wait until you’ve cleared one drug to start another. But Celexa (citalopram) and Lexapro (escitalopram) are vastly more selective than Prozac (fluoxetine), and so the side effect profiles, and pretty much everything else, are very different when you compare Celexa or Lexapro with other SSRIs, but practically identical when compared with each other. While most people couldn’t tell the difference between Lexapro and Celexa,2 because Lexapro is a derivative of Celexa, a few people will respond differently to the two.
3.1 Drugs with Similar Methods of Action as/That Work Like Zyprexa (olanzapine)
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1 Unlike Lamictal, which was originally thought to be be such a potent folate antagonist that it would work well as a treatment for malaria and similar parasites that took up residence in your brain. Or Topamax, which was originally thought to be an awesome drug for type 2 diabetes, as it looked like it would both control weight and blood sugar.
2 The one real difference used to be cost. Now that Lexapro is available as a generic in the US that difference isn't as great as it once was.
If you have any questions not answered here, please see the Crazymeds Zyprexa discussion board. We welcome criticisms of the articles, notifications of bad links, site problems, consumer experiences with medications, etc. I’m not always able to write back. Hence I never answer questions about meds via e-mail that are answered by this or other articles. Especially if they have been repeatedly asked on the forum. That’s why we write these damn things. Questions about which meds are best for your condition should also be asked on the forum; because this is a free site, so the price of admission is making things easier for somebody else searching for the same answer. We don’t deal with children on the forum or in private because after doing this for ten years I don’t have the emotional stamina to deal with kids who have brain cooties. How to contact Crazymeds. — Jerod Poore, CME, Publisher crazymeds.us
|Last modified on Thursday, 13 March, 2014 at 17:06:07 by JerodPoore||Page Author JerodPoore||Date created Wednesday, 20 July 2011 at 11:21:11|
|“Zyprexa Expanded Pharmacodynamics” by Jerod Poore is copyright © 2011 Jerod Poore||Published online 2011/07/20|
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|Plain text:||Poore, Jerod. “Zyprexa Expanded Pharmacodynamics.” crazymeds.us. (2011).|
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1 While there are plenty of books to help you with hypochondria, for some reason there’s not much in the way of websites. Then again, staying off of the Internet is a large part of curing/managing the disorder.
2 Remember kids, Microsloth operating systems are like TOS Star Trek movies with in that every other one sucks way, way more. With TOS Star Trek movies you don’t want to bother watching the odd-numbered ones. With Microsloth OS you don’t want to buy and install the even-numbered ones. Anyone who remembers ME and Vista knows what I mean.
3 Have I mentioned how open source operating systems for commercial applications is one of the dumbest ideas in the history of dumb ideas? I don’t even need my big-ass rant any more. Heartbleed has made my case for me. And that’s just the one that got all the media attention. The very nature of an open source operating system makes security as much of an illusion of anonymity. Before you flip out too much: the domain Crazymeds is hosted on uses a version of SSL that is not affected by the Heartbleed bug. That’s one of the many reasons why I pay a lot of money and keep this site on Lunarpages.