Listening to Prazosin Part 1

I remember where I was when I first heard a lecturer speak about prazosin.  I was struck by his willingness to speak against the conventional doctrine of psychiatric care for Post Traumatic Stress Disorder (PTSD).  I’ve heard medications touted before but this man’s tone of confidence mixed with realizing that what he was saying was not what we expected to hear on this topic.  I was listening to a continuing medical education program on my way to work and this is when my career began to gravitate towards treating the re-experiencing of trauma as if there was nothing else more important.  Truthfully, I was not instantly convinced by his words or even his tone.  Really all it took to convince me was to use prazosin once or twice and see in front of me the transformation in my patient.  Since then, I have become a proponent of prazosin as anyone who knows me or ends up talking to me at any function can attest.   I want to tell you the story of what I have learned by “listening to Prazosin”.  

I found the book Listening to Prozac by Peter D. Kramer to be interesting and refreshing.  It is in fact stating the obvious that Prozac can help patients with problems that before Prozac would require long psychoanalysis or hazardous medications.  I found it interesting that he felt the need to share his amazement about how this could be possible from a simple serotonergic medication.  I appreciate that he stopped to tell this story.  I appreciate it when experienced clinicians share their insights, not just regurgitate large study outcomes.  

Why does this story need to be told?  Well, in my opinion, and to my frustration, prazosin’s benefit is not fully appreciated by clinicians and barely known about by the public who may know someone with re-experiencing of trauma.  If one was to examine the research on prazosin chronologically, one might be impressed at the brilliant discovery and portfolio of thorough papers produced by Murray Raskind MD and his team.  The studies were not that large but the effect was replicated and pronounced.  If one were to look at the research starting with the largest study to date, one would conclude that prazosin is completely ineffective.  The largest study showed that prazosin did not outperform placebo in treating PTSD or even reducing nightmares.  

Could you imagine a study across America that tried to show that sunglasses benefitted the wearer and for some reason concluded that sunglasses were no more effective than clear-lens glasses.  Would you stop wearing sunglasses or would you question what went wrong with the study?  The size of the effect of wearing sunglasses on a sunny day is large and some would even say undeniable.  The benefit seen when prazosin is used to treat nightmares is also large and, in my opinion, undeniable.  Therefore, one should not abandon it in the face of a study that curiously did not show any benefit.  

I want to tell you that prazosin is effective and that it is safe.  Prazosin has been around since the 1980’s and is no longer used much for it’s FDA indication as a blood pressure medication because there are now many more effective and better tolerated medicines for that.  Nevertheless, prazosin is FDA approved and has a lot of safety data.  The only case of overdose was of a toddler who took 40 times the starting dose of prazosin and after brief treatment was absolutely fine and their blood pressure remained normal through the whole ordeal.  

Many physicians tell me that they don’t feel comfortable prescribing prazosin because of the possibility of causing low blood pressure and this is a possibility according to the safety data.  However, any time we give a blood pressure medication, there is a possibility of causing low blood pressure and we still treat high blood pressure because the side effect is unlikely to happen and the result of not treating high blood pressure is bad.  

I have prescribed prazosin to hundreds of patients and the number who became dizzy after the first dose and the number who actually developed low blood pressure could be counted on two hands.  I also have patients on dozens of milligrams of prazosin and their blood pressure is completely normal.  It really makes me question what I learned about alpha-blockers in medical school.  I think the body’s homeostasis is the explanation for this lack of effect on blood pressure. 

We all know that acetaminophen (Tylenol) lowers a fever, yet we don’t worry that when we take it for a headache that our body temperature will drop.  A fever is when the body is out of homeostasis and when our temperature is normal we are in homeostasis.  Our bodies like homeostasis and are capable of keeping us in a happy homeostasis most of the time.  When a person has high blood pressure they are out of homeostasis, but when they have normal blood pressure they are in homeostasis.  This is why I confidently give prazosin to patients and rarely see a side effect or effect on their blood pressure.  

Prazosin is not entirely benign in all people but the side effects can be anticipated and managed.  I’m a geriatric psychiatrist and I have started 90-year-olds on prazosin and they have benefited without side effects.  Almost all the studies of prazosin for PTSD show that the effect on blood pressure is minimal and not significant.