Posted by Stan on April 20, 2003, at 0:28:12
In reply to SSRI's increasing effects of Benzodiazepines?, posted by lady fever on April 19, 2003, at 16:55:35
> Question two, for anyone interested in pharmacological interactions, as I am:
>
> I'm noticing on Celexa that I can't stomach my usual Xanax, it makes the side effects much stronger, and my Xanax is literally knocking me over, totally sedating, so wiped out and stoned feeling, I remember this when I started it 7 years ago, but not since then.
>
> Why?
>
> I don't buy the "because it's decreasing your anxiety" bit because I haven't had a panic attack in years, not sure if I even have it anymore. I take Xanax at this point because I have muscle twitching (myoclonus): originally I took Valium, but it made me drowsy, so my neurologist switched me to Xanax, and it made me less drowsy, so I kept on it. I don't have generalized anxiety or anything.
>
> Why would an SSRI increase the side effects of a Benzodiazepine?
>
> It's kind of nice, actually, I am able to avoid the in between dose withdrawal thing, though my myoclonus has come back fiercely, but it seems odd to me? Do Serotonin and GABA have anything to do with each other? Is the side effect from something else?
>
> Anyone know? It's odd.>>>>>>>>>>>>>
i'd recommend a switch to ativan, which is quite similar, with the important difference that it is primarily cleared by the kidneys and not the liver. xanax interacts with several SSRIs & SNRIs and certain other psych-meds in such a way that it's effects become increased fairly sharply. i had this problem with a xanax/serzone combo and had to take 1/2 the typical xanax dose and ultimately switch to ativan because the effects were so unpredictable. if you don't have a package insert for the xanax, get one from your pharmacy and read the "precautions" section along with other areas devoted to drug interactions. get a brand-name insert, even if you are taking the generic -- the alprazolam ones usually aren't as thoroughly written.
i have an old insert from years ago and i don't know the generic name for celexa -- celexa might not have been introduced at the time this was written or perhaps i don't recognize its generic if it's featured at all. there are precautions regarding coadministration of xanax with prozac, luvox, serzone, and others. these are drugs whch are metabolized to a large extent by a particular liver enzyme called P450 3A (CYP 3A). plasma concentrations of xanax rise markedly in most people who take these ADs with xanax, sometimes doubling. half-life is extended, with the potential of doubling in some cases as well, as the body takes longer to clear the drug. there are more precise percentages listed in the insert.
i just found a little chart that gives me the generic name for celexa (citalopram) and supposedly it has as one of its strong points the fact that it exerts little or no inhibitory action on that liver enzyme i named in the prior paragraph, so maybe i typed all of this in vain :-(. sorry -- maybe someone taking the other three ADs i mentioned along with xanax will be inspired to read their xanax insert and adjust their dosage accordingly.
in short, i don't know why the xanax is hitting you harder, unless it's interacting with the celexa in a way that doesn't heavily involve that particular enzyme. hope i didn't get you worried in the beginning portion of my post -- i still think ativan is good choice in general when compared to xanax because the kidneys handle most of its processing and you can avoid some problematic situations with the liver enzymes causing dramatic flucuations in blood levels. you have to take about twice as many mg of ativan as xanax to get a similar effect and the half-life is a little longer. it also takes a bit longer to start to "work" after a dose is taken (about 40 min vs 20 min, in my experience. good luck.
Stan
poster:Stan
thread:220714
URL: http://www.dr-bob.org/babble/20030417/msgs/220772.html