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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 10 of 10. This is the beginning of the thread.
Posted by big time on June 26, 2007, at 19:58:47
hi,
i have bipolar 1 and i take lithium and zyprexa. i want to decrease the zyprexa and increase the lithium, but my pdoc is hesitant to increase it. does anyone have experience with high doses of lithium for maintenance therapy for BD? i know its really old school, but i want to try it
thanks!
Posted by Larry Hoover on June 26, 2007, at 21:50:29
In reply to high dose lithium, posted by big time on June 26, 2007, at 19:58:47
> hi,
>
> i have bipolar 1 and i take lithium and zyprexa. i want to decrease the zyprexa and increase the lithium, but my pdoc is hesitant to increase it. does anyone have experience with high doses of lithium for maintenance therapy for BD? i know its really old school, but i want to try it
>
> thanks!You can't increase your lithium as you might increase other drugs. Lithium has what is called a narrow therapeutic index. What that means is the dose that is effective is not very much lower than the dose that is toxic. That's why you have to have blood tests done when you go on lithium. You might be able to increase your lithium by a little bit, but only under close medical supervision. You'd also have to understand the extra risk that accompanies moving towards the higher blood concentrations of lithium. You have to be much more careful about fluid intake, excercise, exposure to heat, and so on. Your pdoc is hesitant for good reason.
What you might consider instead is finding a different drug to combine with your lithium.
Lar
Posted by big time on June 26, 2007, at 22:31:19
In reply to Re: high dose lithium » big time, posted by Larry Hoover on June 26, 2007, at 21:50:29
Lar,
Thanks for responding.
> What you might consider instead is finding a different drug to combine with your lithium.
I'm thinking about Abilify, but I got bad akathesia on Haldol and i've heard Abilify causes akathesia too. I know there are other atypicals, but its kind of scary because they really redraw your landscape, as i guess a lot of these drugs do. I would love to get off Zyprexa so i don't get diabetes, but it is such a great drug when you're in a pinch, so i'm reluctant to let it go.
thanks again
Posted by Squiggles on June 27, 2007, at 6:22:07
In reply to high dose lithium, posted by big time on June 26, 2007, at 19:58:47
> hi,
>
> i have bipolar 1 and i take lithium and zyprexa. i want to decrease the zyprexa and increase the lithium, but my pdoc is hesitant to increase it. does anyone have experience with high doses of lithium for maintenance therapy for BD? i know its really old school, but i want to try it
>
> thanks!
Hi,I wonder what your lithium dose is? I take 900mg per day-- i would prefer lower but my dr. wants the blood level where it is 0.8-1.2. Frankly, i have never been observed on a different blood level, but i trust my doctor.
As for the combo, you may want to look at the interactions between Zyprexa and Lithium:
http://www.drugs.com/drug-interactions/zyprexa_d04050.html
The narrow therapeutic index: ah, yes, well after many yrs. of experience, i would say that it depends very much more on dietary and sodium/potassium/water balance. cumulative toxicity AND interaction with other drugs.
I think that it being such an old drug, it has been monitored for this danger, far more than other drugs which also have a toxity level. "Narrow" is a vague concept when it is not given in actual numbers, and all that is indicative is the actualy toxicity after the fact.
Squiggles
Posted by Larry Hoover on June 27, 2007, at 19:20:38
In reply to Re: high dose lithium » big time, posted by Squiggles on June 27, 2007, at 6:22:07
> Hi,
>
> I wonder what your lithium dose is?I wonder why you think it matters? We've been over these concerns before, and I must reiterate that your attitude towards the use of lithium might be dangerous if adopted by other persons.
The very same lithium dose, when taken by different individuals, will result in different blood lithium concentrations. That is why lithium is never titrated by dose, but instead, by blood concentration.
> I take 900mg per day-- i would prefer lower but my dr. wants the blood level where it is 0.8-1.2.
That is the normal therapeutic blood concentration. The dose that gets you there is idiosyncratic, although your dose is rather typical, nonetheless.
> The narrow therapeutic index: ah, yes, well after many yrs. of experience, i would say that it depends very much more on dietary and sodium/potassium/water balance. cumulative toxicity AND interaction with other drugs.
More so than dose? Not true. These latter variables influence the blood concentration, absolutely, but they are lesser management factors than is dose itself. In an individual, blood concentration is linear with dose.
> I think that it being such an old drug, it has been monitored for this danger, far more than other drugs which also have a toxity level. "Narrow" is a vague concept when it is not given in actual numbers, and all that is indicative is the actualy toxicity after the fact.
There is nothing at all vague about the narrow therapeutic index issue for lithium. It has an index of 2.
From the monograph:
"Adverse reactions may be encountered at serum lithium levels below 1.5 mEq./l. Mild to moderate adverse reactions may occur at levels from 1.5 to 2.5 mEq./l., and moderate to severe reactions may be seen at levels of 2.0 mEq./l. and above.
Diarrhea, vomiting, drowsiness, muscular weakness, and lack of coordination may be early signs of lithium intoxication, and can occur at lithium levels below 2.0 mEq./l. At higher levels, ataxia, giddiness, tinnitus, blurred vision, and a large output of dilute urine may be seen. Serum lithium levels above 3.0 mEq./l may produce a complex clinical picture, involving multiple organs and organ systems. "
In the standard practise of medicine, the occurrence of moderate to severe toxic reactions at 2.0 mEq./l, with therapeutic levels arising in and around 1 mEq./l, the therapeutic index (the ratio of toxic dose to therapeutic dose) is 2.
Lithium toxicity is no joke, and is not the least bit overstated.
Lar
Posted by Squiggles on June 27, 2007, at 20:09:37
In reply to Re: high dose lithium » Squiggles, posted by Larry Hoover on June 27, 2007, at 19:20:38
I know all that. But once your doctor
has established a satisfatory dose for you,
the anything beyond that, is due to the
extra-therapeutic factors i mentioned.And btw, you can feel your dose going toxic,
as you can with other antidepressants and antipsychotics with extrapyramidic effects.
It's just that lithium is so well-publicized.
Other drugs can kill you from crossing the narrow therapeutic index too, e.g. imipramine's cardiac
toxicity effects, to mention one.Squiggles
Posted by Larry Hoover on June 29, 2007, at 7:35:53
In reply to Re: high dose lithium » Larry Hoover, posted by Squiggles on June 27, 2007, at 20:09:37
> I know all that. But once your doctor
> has established a satisfatory dose for you,
> the anything beyond that, is due to the
> extra-therapeutic factors i mentioned.I am not literally concerned with your knowledge, but instead, the potential to mislead the lurking public. You are correct, but simultaneously not. Oscillations in lithium blood concentration which enter the realm of toxicosis could not possibly occur absent sufficient underlying intake (the daily dose), the primary factor. That we have identified the secondary factors which influence blood concentration oscillations in the short term is not sufficient argument to implicate them in the toxic reaction. They are simply the secondary variables of concern when a subject is subjected to near toxic intake of a toxicant with a narrow therapeutic index. Once the therapeutic baseline is established by dose (primary factor), perturbations in that baseline must be minimized (secondary factor(s)).
This is not an argument of semantics. Lithium is toxic in all doses. The frank toxicosis is a graded response only slightly elevated from the sub-acute toxicosis we call therapeutic.
> And btw, you can feel your dose going toxic,
> as you can with other antidepressants and antipsychotics with extrapyramidic effects.You completely misunderstand, as demonstrated by this argument. Side effects are quite distinguishable from toxic effects. Lithium toxicosis involves disruption of sodium channels, an effect for which there is no physiological means by which the body can overcome it, until such time as it can reduce the concentration of lithium ions (if it survives the toxic effect). Extrapyramidal side effects are regulatory in nature.
Notwithstanding those who take the position that psych meds are poisonous, the term does not apply to any antidepressant or antipsychotic at doses even uncommonly employed in therapeutic interventions.....their therapeutic indices are typically in the 100's or 1000's (or undefined, being so large as to not be relevant).
> It's just that lithium is so well-publicized.
No, it's not, or I wouldn't belabour the issue. You're arguing with a toxicologist.
> Other drugs can kill you from crossing the narrow therapeutic index too, e.g. imipramine's cardiac
> toxicity effects, to mention one.
>
> SquigglesSituations like you are suggesting are idiosyncratic in nature. They do not happen to all (or even most) subjects at the same dose. Far from it.
Example: The black box warning on nefazodone arose due to rare toxic reactions involving fulminant liver failure. However, those deaths were exceptional. The LD50 was not changed by these occurrences. The therapuetic index for this drug was not changed. It was simply recognized that rare idiosyncratic toxicoses can occur, and the risk/benefit analysis had to take these occurrences into account.
Lithium toxicosis is the general occurrence. It happens to all subjects so exposed, with only minor variation in the specific (individual) concentrations at which the specific symptoms of the toxicosis arise.
My point is how different lithium is from all other drugs in common use. Even calling it a drug is really a misnomer. It is a prescription substance because of the risk of toxicosis. There is no other reason.
Lar
Posted by Squiggles on June 29, 2007, at 7:40:24
In reply to Re: high dose lithium » Squiggles, posted by Larry Hoover on June 29, 2007, at 7:35:53
Well, i guess my doctor must know all that
otherwise i'd be dead now, after taking it
for 25 years. Are you a doctor, by any chance?Squiggles
Posted by Larry Hoover on June 29, 2007, at 10:28:26
In reply to Re: high dose lithium » Larry Hoover, posted by Squiggles on June 29, 2007, at 7:40:24
> Well, i guess my doctor must know all that
> otherwise i'd be dead now, after taking it
> for 25 years. Are you a doctor, by any chance?
>
> SquigglesNo. I'm a toxicologist.
Lar
Posted by Squiggles on June 29, 2007, at 10:52:08
In reply to Re: high dose lithium » Squiggles, posted by Larry Hoover on June 29, 2007, at 10:28:26
> > Well, i guess my doctor must know all that
> > otherwise i'd be dead now, after taking it
> > for 25 years. Are you a doctor, by any chance?
> >
> > Squiggles
>
> No. I'm a toxicologist.
>
> Lar
>Do doctors consult toxicologists on such
dangerous drugs as lithium, in your experience?Squiggles
This is the end of the thread.
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