As time goes by, the memory may be harder to remember, but the legacy is hard to forget.

We have windows of opportunity for altering the closure of fearful memories in the brain.
The time window for dampening the initial locking-in of memories is on the order of 6 hours.
 So pharmacological approaches to lessen the strength with which a distressing memory is locked into the brain need to be administered within that short window. Indeed, there is emerging evidence from rodent and human studies that drugs called beta-blockers can achieve a reduction in later PTSD symptoms if administered quickly. But new research is suggesting that even beyond the short window during which memories are saved to the internal hard drive of our brain, they can be retrieved, updated, and toned down.