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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 5 of 5. This is the beginning of the thread.
Posted by den2 on July 11, 2003, at 22:33:34
Mirtazapine
As with all drugs, knowledge of the in vitro pharmacology of mirtazapine can help us understand its clinical pharmacology. Mirtazapine's most potent site of action is the histamine-1 receptor (Figure 1). At higher concentrations, the drug sequentially blocks the 5-HT2A receptor and then the alpha-2 adrenergic receptor (Figure 1). Although not illustrated in Figure 1, mirtazapine binds almost as avidly to the 5-HT2C and 5-HT3 receptors as it does to the 5-HT2A receptor.3,4
Doses of mirtazapine needed to treat clinical depression result in concentrations sufficient to block the 5HT2A, 5-HT2C, 5-HT3, and the alpha-2 adrenergic receptors. Higher concentrations (and hence doses) are obviously needed to block the alpha-2 adrenergic receptor site than are needed to block the serotonin receptors. These facts are consistent with the hypothesis that one or more of these mechanisms mediate the antidepressant efficacy of mirtazapine. This constellation of mechanisms of action is not shared by any other antidepressant, which raises the possibility that mirtazapine might work in patients who have not benefited from other types of antidepressants. There is some evidence supporting this possibility. Two separate studies have indicated that mirtazapine can work in patients who have not benefited optimally from treatment with amtriptyline11 or fluoxetine.12
If i read correctly on mirtazapines website..it says that alpha 2 antagonism starts at 15mgs. IT also says that higher doses are needed to block the alpha 2 receptor than is needed to block the 5ht2 5ht3 receptors. My question is ... dose it only take 7.5 mgs to block 5ht2 and 5ht3 receptors while not getting the alpha 2 antagonist effect until 15mgs?
Posted by Maximus on July 12, 2003, at 14:04:35
In reply to remeron question, posted by den2 on July 11, 2003, at 22:33:34
>My question is ... dose it only take 7.5 mgs to >block 5ht2 and 5ht3 receptors while not getting >the alpha 2 antagonist effect until 15mgs?
My understanding is that you get thoses blockades via alpha 2 antagonism at all doses. But at lower doses like 7.5 mg or 15 mg the antihistasmine reuptake is more "evident".
To put it simple, you have this modulation of 5-HT neurotransmission (5HT2C and 5HT3) via the blocking on pre- and postsynaptic alpha-2 adrenoceptors.
Good luck!
Max
Posted by McPac on July 13, 2003, at 23:57:43
In reply to Re: remeron question » den2, posted by Maximus on July 12, 2003, at 14:04:35
Any idea what is the MINIMUM dose that seems to be effective in depression for most folks on Remeron?
Wonder if only 15 mg has ever been effective for many people.
Posted by Maximus on July 14, 2003, at 9:35:52
In reply to Re: remeron question, posted by McPac on July 13, 2003, at 23:57:43
> Wonder if only 15 mg has ever been effective for many people.
15 mg??? Probably just for insomnia.
30 mg is the minimum dose for depression.
Posted by McPac on July 14, 2003, at 13:39:42
In reply to Re: remeron question » McPac, posted by Maximus on July 14, 2003, at 9:35:52
Max,
I was reading a 'Remeron board' on-line (at another site) and one Remeron user was saying that at least a few folks (including himself) were only taking 15 mg for depression.....who knows?
This is the end of the thread.
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