Posted by AndrewB on May 1, 2000, at 8:44:50
In reply to Re: Shorter Trials with ADs, posted by Scott L. Schofield - SLS on April 30, 2000, at 22:40:15
Scott,
I can see that you didn't find much to agree with in my post. You didn't even agree with my name it seems!
Concerning 2 week vs. 3 week or longer trials with tricyclics and MAOs, I'm open to what you have to say. Studies and their conclusions can be wrong. But I tenatively agree with the idea itself behind 2 week trials; if after two weeks of taking an MAOI or a tricyclic a person should in good likelihood (70%-80%) have seen improvement, then it is time to move on to a new med. Let me know why you think the way you do.
Concerning the D2/D3 agonists pramipexole and ropinirole, I'm not ready to say they are as efficious or as long lasting as amisulpride or sulpiride. But neither am I as certain as you are that they aren’t. I understand why you feel the way you do, knowing what you do about bromocriptine and the other older agonists. But perhaps these are different. At least one small study has indicated that pramipexole is long lasting (6 months). As far how effective it is on its own I’ll wait to hear other people’s personal experiences with it.
Yes, D2 agonists act on the postsynaptic receptor and a drug like amisulpride acts on the presynaptic (at low doses). But I don’t see this as a big difference. In the end, amisulpride acts via stimulation of the postsynaptic receptor, just as pramipexole, the only difference being that the postsynaptic stimulation is done by the body’s dopamine instead of an agonist. Whether an agonist or the body’s dopamine is involved, the same issues of upregulation and downregulation and receptor sensitivities are involved and the effectiveness of amisulpride demonstrates that long term stimulation of the D2/D3 receptors does not need to lead to poop out. But I have to admit, I’m sure there is a lot I don’t understand here.
To answer your question, it has been my personal experience that both amisulpride and mirapex act in about 1 to 4 days.
And yes, amineptine has been described as a direct acting DA medicine in relation to SSRIs and other ADs. It is all relative you know!
Finally, we both may agree that some of the D2/D3 receptors are located in parts of the brain central to some aspects mood (the limbic system). Causes of D2/D3 hypofunction that I have read of include lesions in the area and stress induced downregulation. Regardless of the ultimate cause of the downregulation, some D2/D3 active medicines have been shown to be efficious in upregulating D2/D3 receptor function on an ongoing basis.
Thank you for your stimulating and well informed disagreements. Best wishes as always,
AndrewB
poster:AndrewB
thread:31785
URL: http://www.dr-bob.org/babble/20000429/msgs/31824.html