According to a study published in the journal Molecular Psychiatry, Clonidine, a drug used to treat high blood pressure, can be used to treat PTSD because it works on adrenergic receptors in the brain. The researchers revealed that androgenic receptors are activated in PTSD and that they play an important role in traumatic memory consolidation.

The researchers stated that guanfacine, clonidine’s sister drug, can also activate these receptors. In the study, the researchers observed that these two drugs bound to the same receptor but showed different outcomes. The results showed that clonidine provided immediate relief to a significant number of people who were suffering from PTSD caused by the current pandemic. It also showed a similar result in people with PTSD from longer-established causes like war and other violence.

When they studied the effect of clonidine on the human brain, they observed that in the hippocampus, there is a novel axis on an adrenergic receptor called a2A, which is essential to maintaining fear memories. They found that a protein called spinophilin interacted with cofilin in the synapse of the neuron present in this axis. This interaction is used to control protrusions in the dendritic spines, leading to the consolidation and storage of memories.

Hence, when the researchers applied clonidine to these neurons, they found that it interfered with cofilin’s exit by encouraging it to interact with the receptor, which consequently interfered with the dendritic spine’s ability to resume a mushroom shape and retain the memory. However, guanfacine did not affect this key player, cofilin. 

(Source: https://theprint.in/health/ptsd-could-potentially-be-treated-by-blood-pressure-medicine-research/1300460/ )