Posted by Larry Hoover on May 17, 2006, at 7:55:46
In reply to Does taking MORE Seroquel make you LESS sedated?, posted by UgottaHaveHOPE on May 16, 2006, at 20:31:46
> Thats what I have heard some people on here say. I took 25mg only for eight months and it made me very tired. Then I had some financial issues, got really jacked up, am taking 300mg per day and dont seem to be as tired. Can someone explain this to me?
The sedating response is non-linear. We are accustomed to assuming that the greater the dose, the greater the effect, but there are exceptions. This is one such exception.
At lower doses, there is that familiar increasing dose/increasing effect pattern, but that changes as you near or exceed the saturation dose for the (presumably) histamine receptors in your brain. If you were to look at a graph of dose against drowsy response, it would actually look something like the traditional bell curve. In the literature, it's called an inverted-U dose response curve.
So at lower but increasing doses, your response i.e. drowsiness, also increases. You're climbing up the left side of the bell curve. At some point, as you approach the saturation point for your receptors, the response levels off. You've reached the maximum, the highest point on the bell curve. There may or may not be some sort of plateau at the top, but, with even greater doses, you start to fall down the right side of the bell curve.
It can be a dramatic fall, or it can be gradual. Everybody is different, and one person may saturate at a very different dose than does the next guy. But, once you get to a high enough dose, your brain simply ignores the signal coming from its saturated receptors. It's as if your brain realizes there's something totally messed with those receptors, and it invalidates their function entirely.
Over time, your brain can adapt to this effect, so dose adjustments may have to be made. I also want to emphasize that there are other effects of this drug which *do not* follow this inverted U dose responsivity. Most of the drug effects are dose-proportional, the way we normally think about drug effects.
Lar
poster:Larry Hoover
thread:644933
URL: http://www.dr-bob.org/babble/20060515/msgs/645078.html