In the immediate aftermath? I’m not sure.
However in the long run you can try things like the following:
EMDR. Trauma overwhelms the amygdala and hippocampus, so the memory can’t be processed into long term storage. bilateral stimulation helps activate the amygdala and hippocampus so when you combine bilateral stimulation with thinking about trauma, it helps it process the memory through the limbic system so it can be processed as a past memory by the frontal cortex
Progranolol therapy - I had a lot of good luck with this. Everytime you relive a traumatic memory, your brain has to pull it out of storage. For the next 6 hours, the memory is more fragile because your brain had to pull it out of memory (don’t ask me how it works, I have no idea). However in order for the brain to put the memory back into storage, it has to attach adrenaline to adrenaline receptors in the brain. So you take 40mg of propranolol, then you wait an hour, then you do intensive exposure therapy where you discuss your trauma. Then 2 hours after your session you take another 40mg of propranolol. These 2 doses of propranolol will block the adrenaline receptors in your brain, so your brain has trouble putting the memory back into storage after it takes it out.
Stellage ganglion block - There is a bundle of nerves in the neck that communicates with the amygdala. When you numb the nerves, the brain senses ‘theres no danger, we can pare back the neural connections in the sympathetic nervous system’.
I wrote a thread about some of this stuff here.
For me, propranolol therapy and a stellate ganglion block were both very helpful for my PTSD.
A big part of PTSD therapy is down regulating the sympathetic nervous system and upregulating the parasympathetic nervous system. Thats not all there is to it, but its a major factor.
There is also vagus nerve stimulation, which can help with this too.