Posted by Racer on May 26, 2006, at 10:30:38
In reply to Re: What should I consider for long term treatment, posted by jealibeanz on May 26, 2006, at 1:48:50
> So, if increased hunger were not an issue, could the serotonin cause some other change in the body that would cause rapid and abnormal weight gain?
Well, you're right that no one really knows why these drugs cause weight gain, but that doesn't mean that they don't. And it'snot really surprising that the mechanism isn't well known yet, since the idiots who prescribe them sometimes *still* tell you that Prozac causes weight loss! Sure, it does, yeah -- for the first three months, then it changes...
Theory I read that makes most sense has the three pronged approach, and I'm brain dead right now, so will likely get this wrong:
5-HT3 receptor mediates bowel motility. That would cause the inital GI distress a lot of people get with SSRIs, as those receptors get stimulated by the 5-HT hanging out in those synapses. Then, once you've been on it a while, your 5-HT3 receptors start to say, 'ah, geeze -- that's too much, I'm not listening to you anymore...' and get less responsive. Now, that's adaptive, but it can also mean that everything in your GI tract slows down. So, if you're constipated on these drugs, as I always am, then you may gain weight as there's more time for nutrients to be pulled from your gut.
They also affect the receptors that tell you you're hungry, or you're full. Those are probably pretty important, although they're not the whole story. I can't speak to the issue of whether they cause more eating, but they DO cause more hunger/appetite. That's not the whole story, either, though.
They also sedate a lot of people, and that includes biological processes. Basically, your metabolism gets groggy. That's got a LOT to do with it. I can barely get out of bed on most of the SSRIs -- other than those that have me turning inside out with miserable anxiety -- and that gets reflected in my weight. Even if I made it to the gym on Paxil, and got through my whole routine, I know I wasn't using nearly as many calories to do it, because I was so groggy through the whole thing.
Sucked a lot.
>Why would Nardil, but not Parnate cause this side effect as well?
Because they're different drugs?
Probably because, while these drugs are in the same class, and have the same basic mechanism of action, they act differently. Even if the main effect is to destroy MAO, they'll both have minor effects, too. Weight gain on Nardil is one, agitation on Parnate is another. And they don't happen for everyone, but that really doesn't help when it happens to you. (I can never understand why someone would think we'd feel better hearing that they *didn't* gain weight on these drugs -- just makes me sure that there's something wrong with me. {shrug} Guess it makes sense to them...)
Anyway, I hope you find something that helps. But I also hope that you get evaluated by someone with a specialty in eating disorders. I am certainly not saying that your weight gain on the meds isn't real. I'm sure it is. What I know, though, is that you're writing things here that I have written; and I know that those most likely to gain weight from these drugs are those who are underweight to begin with, often those with eating disorders.
Good luck.
poster:Racer
thread:647484
URL: http://www.dr-bob.org/babble/20060525/msgs/648813.html