Originally Posted by mrsD

The way tricyclics work is in the brain, where they tweak serotonin receptors to ignore pain signals.

So the sedation does come right away, but the real actions take weeks to manifest. The drug has to get to the centers necessary and thru the blood brain barrier, both situations that take time.

Nortriptyline and amitriptyline both show potential for peripheral nerve improvement by affecting nerve growth factors. This is also a slow process.