Prazosin is orally active and has a minimal effect on cardiac function due to its alpha-1 receptor selectivity. However, when prazosin is started, heart rate and contractility go up in order to maintain the pre-treatment blood pressures because the body has reached homeostasis at its abnormally high blood pressure. The blood pressure lowering effect becomes apparent when prazosin is taken for longer periods of time. The heart rate and contractility go back down over time and blood pressure decreases.
The antihypertensive characteristics of prazosin make it a second-line choice for the treatment of high blood pressure.
Prazosin is also useful in treating urinary hesitancy associated with prostatic hyperplasia, blocking alpha-1 receptors, which control constriction of both the prostate and urethra. Although not a first line choice for either hypertension or prostatic hyperplasia, it is a choice for patients who present with both problems concomitantly.
This medication has shown to be effective in treating severe nightmares in children and people with PTSD symptoms. Veterans have also been treated successfully at Seattle’s VA Puget Sound Health Care System (VAPSHCS) for sleep disturbance related to PTSD. Doses are lower for this purpose than for control of blood pressure.
Prazosin holds promise as a pharmacologic treatment for alcohol dependence after a 2009 pilot trial was completed. A larger controlled Phase II “Clinical Trial of the Adrenergic Alpha-1 Antagonist Prazosin for Alcohol Dependence” is currently underway.
The drug is usually recommended for severe stings from Indian Red Scorpion Hottentotta tamulus in Indian Subcontinent…
Wow, that’s a lot of uses for just one drug. I didn’t know that doctors were prescribing blood pressure medication for PTSD. It is also used off-label for chronic pain (although it didn’t help me).