Posted by linkadge on July 2, 2016, at 9:02:00
In reply to Measuring Drugs Activity at Receptors, posted by Hello321 on July 1, 2016, at 10:30:25
Hi,
According to the site I posted,
Cyrproheptadine (5-ht2c ki) ~ 12
Suprisingly this site doesn't yet have data on pimavanserin. However, if the Wikipedia data is correct, it has a much lower ki (thus higher affinity).
Pimavanserin (5-ht2c ki) ~ 0.44
Now, the real thing you are interested in is the ratio of affinities between different receptors.For example (5-ht2c/5-ht2a ratio)
Cyproheptadine = 12 / 2.5 = ~ 5. In other words it is 5 time more active at 5-ht2a than 5-ht2c.
However,
Pimavanserin = 0.44 / 0.087 ~ 5. So, similarly, it too, is approximately 5 times more active at 5-h2a than 5-ht2c.
If you are looking for something to selectively block 5-ht2c, than these drugs may not be the best options. However, if you had to choose between the two (on paper) I'd select pimvanserin, mainly because it has lower affinity for dopamine, histamine etc. Cyproheptadine is fairly dirty in the sense that it binds to dopamine, adrenaline, calcium channels, histamine etc, in the same range as 5-ht2a/c.
Really, the ratio is more important, because, even if the Ki is high, you could take more drug. However, in the case of cyproheptadine, higher doses would also hit other receptors.
On paper, pimavanserin looks interesting. I currently take mirtazapine (mainly for sleep) however, it hits histamine pretty hard. It might be nice to try a more selective 5-ht2a/c antagonist, to see how it augments venlafaxine with possibly less sedation.
Linkadge
poster:linkadge
thread:1090060
URL: http://www.dr-bob.org/babble/20160609/msgs/1090088.html