Posted by linkadge on January 5, 2019, at 18:58:12
In reply to Re: Mirtazapine (remeron) as SSRI add-on therapy?, posted by mtom on January 5, 2019, at 12:00:15
>Why would lower dosages of Mirtazapine be more
>sedating than higher dosages?Yeah, just to mirror what ChristEmpowered said...
Basically, any drug has varying 'affinity' for a variety of receptors. Affinity is how strongly the drug likes to bind to one receptor relative to a different type.Mirtazapine has very strong affinity for H1 (blocks histamine receptors which causes sedation), next to that, it binds to serotonin receptors (5-ht2a,2c and 5-ht3 which can relieve some of the side effects of SSRIs like anxiety, sexual dysfunction, insomnia etc). After that, it binds to NE receptors, where it causes norepinephrine release.
Think of it like filling a champaigne glass. You pour the wine into the first glass. Once that glass gets filled it pours over into the next glass and so on and so forth.
Mirtazapine will preferentially bind to histamine receptors. However, as more and more histamine receptors get blocked with higher doses (i.e. receptor saturation), more drug will float around more and bind to its secondary target.
So, in low doses, it mostly fills histamine receptors causing sedation. In higher doses, you get the norepinephrine binding, which counteracts the antihistamine effect.
I found 0-7.5mg very sedating. I found 15mg a little less so sedating and 30mg almost 'neutral' although there is still some wonkiness untill the receptors get more balanced out.
Linkadge
poster:linkadge
thread:1102691
URL: http://www.dr-bob.org/babble/20181024/msgs/1102697.html