It looks like trazodone antagonizes the serotonin receptors which is blocking them while also preventing the reuptake of serotonin which increases the concentration of serotonin in the synapse. I would have to do more research to figure out exactly how it’s working.
“It is a phenylpiperazine compound of the serotonin antagonist and reuptake inhibitor (SARI) class”
“The main objective of a reuptake inhibitor is to substantially decrease the rate by which neurotransmitters are reabsorbed into the presynaptic neuron, increasing the concentration of neurotransmitter in the synapse. This increases neurotransmitter binding to pre- and postsynaptic neurotransmitter receptors”
“Serotonin antagonist and reuptake inhibitors (SARIs) are a class of drugs used mainly as Antidepressant, but also as anxiolytics and hypnotics. They act by antagonizing serotonin receptors such as 5-HT2A receptor and inhibiting the reuptake of serotonin Additionally, most also antagonize α1-adrenergic receptors”
“Approximately 90% of the total serotonin is located in the enterochromaffin cells in the GI tract, where it regulates intestinal movements.
However, it is also produced in the [central nervous system”