Propranolol Combined With Reactivation Therapy May Reduce PTSD Symptoms

It would be a tremendous breakthrough in treating posttraumatic stress disorder (PTSD) if patients were able to rid themselves of unwanted traumatic memories. Researchers and clinicians once believed that weakening memories might be an impossible task; however, studies over the past decade have found that when stored memories are retrieved, or reactivated, they temporarily enter a malleable state. Once a person stops thinking about a memory, the memory returns to a stable form, a process known as reconsolidation.

A drug that interferes with the reconsolidation of a reactivated traumatic memory could potentially weaken or even erase the retrieved memory. A study published January 12 in AJP in Advance suggests that the beta-blocker propranolol might be able to block memory reconsolidation.

Adults with PTSD who actively recalled their traumatic event under the influence of propranolol once a week, for up to six weeks, reported a substantial decrease in PTSD symptoms compared with participants who took placebo. This decrease was evident from both the perspective of the patient and clinician.

“The effect sizes obtained for pre-reactivation propranolol in our study compare well to those obtained with the best evidence-based treatment for PTSD, namely, cognitive-behavioral therapy, as well as those obtained with the most recommended pharmacological treatment for PTSD, namely, SSRIs,” Alain Brunet, Ph.D., an associate professor of psychiatry at McGill University in Montreal, and colleagues wrote. “Should these results be replicated in further studies, propranolol blockade of reconsolidation may become a new therapy for some patients with PTSD.”

At the start of the six-week, double-blind, randomized trial, adults who had experienced at least six months of PTSD symptoms were assigned to take either propranolol (administered as 0.67 mg/kg of short-acting propranolol plus 1.0 mg/kg of long-acting propranolol) or placebo one hour before a brief memory reactivation session.

Patients were excluded from the trial if they had a basal systolic blood pressure <100 mmHg; a basal heart rate <55 beats per minute; a medical condition contraindicating administration of propranolol or potentially confounding the results, such as arrhythmia or congestive heart failure; or were currently using medication that may interact adversely with propranolol, such as antiarrhythmic medications or calcium channel blockers. Three people in each group reported side effects after receiving the placebo or propranolol and were excluded from the rest of the trial.

During the reactivation session, the participants were asked to write a one-page trauma narrative, focusing on the most disturbing moments of the traumatic event and including five or more bodily sensations drawn from a checklist. The participants were then asked to read the narrative aloud once to the therapist “as if they were back in the event.”

At subsequent weekly visits, participants again took propranolol or placebo and were asked to re-read the narrative 90 minutes after they took their medicine.

The participants filled out the patient-rated PTSD Checklist Specific (PCL-S) scale at the beginning of each treatment session, before propranolol or placebo was administered. The Clinician-Administered PTSD Scale (CAPS) was also used one week before and one week after the six-week trial.

Both the propranolol and placebo groups had similar PCL-S and CAPS scores at baseline. At the end of the study participants who took propranolol had greater decreases in both measurements that were statistically significant. Pre- to post-treatment CAPS improvements were 38 percent in the propranolol group and 24 percent in the placebo group, while PCL-S improvements were 56 percent in the propranolol group and 15 percent in the placebo group.

The investigators also conducted a six-month follow-up and found that the participants in the propranolol group continued to experience lower symptom scores than the placebo group, even without continued use of propranolol. However, the authors noted that the follow-up data only included 14 participants. “Further studies should make efforts to retain a greater percentage of participants for long-term follow-up,” the authors wrote.

The patients in this study underwent trauma reactivation but did not receive full exposure therapy. Exposure therapy is a commonly used PTSD treatment that seeks to extinguish the link between a memory and the negative behaviors it elicits. While both therapies involve coaching the patient to relive a past traumatic event in some manner, the exposure component of reconsolidation therapy is kept to a maximum of about 25 minutes.

This study was supported by a grant from the U.S. Army Congressionally Directed Medical Research Program. ■