Dr. Adams
12-08-2006, 05:08 PM
The antihypertensive agent guanfacine, which lowers brain norepinephrine activity, does not reduce the symptoms of posttraumatic stress disorder (PTSD). There is evidence from a variety of studies that norepinephrine is over-activated in PTSD. Because of this, experts in the field have recommended guanfacine and clonidine (both alpha 2 adrenergic receptor agonists) as possibly effective in PTSD. However, prior to our study, there were no data from randomized controlled trials.
Guanfacine relative to placebo did not result in greater improvement in PTSD symptoms, depression, general psychological distress, sleep quality or quality of life. The effect size of zero suggests no promise for demonstrating efficacy even with larger samples. Moreover, guanfacine was associated with a number of side effects, including somnolence, lightheadedness and dry mouth.
For chronic PTSD, the key message is to avoid guanfacine and be wary of using a similar drug clonidine -- at least until there are results from randomized controlled studies.
Another antihypertensive medication, prazosin, which has a different mechanism of action than guanfacine and clonidine, has shown promise for the treatment of chronic PTSD in randomized controlled trials.
The important distinction between guanfacine and prazosin is that the latter drug does not lower brain norepinephrine release. Rather, it blocks the effect of norepinephrine on one particular receptor (alpha 1) on the post-synaptic side of the synapse, which may be implicated in anxious arousal." Am J Psychiatry 2006.
Guanfacine relative to placebo did not result in greater improvement in PTSD symptoms, depression, general psychological distress, sleep quality or quality of life. The effect size of zero suggests no promise for demonstrating efficacy even with larger samples. Moreover, guanfacine was associated with a number of side effects, including somnolence, lightheadedness and dry mouth.
For chronic PTSD, the key message is to avoid guanfacine and be wary of using a similar drug clonidine -- at least until there are results from randomized controlled studies.
Another antihypertensive medication, prazosin, which has a different mechanism of action than guanfacine and clonidine, has shown promise for the treatment of chronic PTSD in randomized controlled trials.
The important distinction between guanfacine and prazosin is that the latter drug does not lower brain norepinephrine release. Rather, it blocks the effect of norepinephrine on one particular receptor (alpha 1) on the post-synaptic side of the synapse, which may be implicated in anxious arousal." Am J Psychiatry 2006.