Hi Rene!
I wasn't aware that propranolol was used to treat nightmares. In my clinical experiences, aside from prazosin, we tend to treat some of the presenting symptoms associated with nightmares, including anxiety. I can see how it may be helpful to give an anxiolytic such as Hydroxyzine or Lorazepam. I wasn't too familiar with propranolol for sleep but it appears it can be effective for those experiencing anxiety. According to one study, lipophilic drugs, such as propranolol and metoprolol, can actually increase the waking cycle due to a decrease in REM (TA & C, 1985).
Looking into the effects of propranolol and PTSD-associated symptoms, it appears that it may serve as a prophylaxis for PTSD and may actually reduce the catecholamine levels, thereby inhibiting the consolidation of memory (McGhee et al., 2009). However, the study revealed that the prevalence of PTSD was the same for patients who received propranolol versus those who were not prescribed. The article did concede that more research would need to be done on a larger scale considering the small sample size and the fact that the study was conducted only on burned veterans. But this is an interesting topic and post! Thank you for sharing!
References
McGhee, L. L., Maani, C. V., Garza, T. H., DeSocio, P. A., Gaylord, K. M., & Black, I. H. (2009). The effect of propranolol on posttraumatic stress disorder in burned service members. Journal of Burn Care & Research, 30(1), 92-97. doi:10.1097/bcr.0b013e3181921f51
TA, B., & C, A. (1985). Beta-blockers and sleep: A controlled trial. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/2865152