Terazosin for PTSD-Related Sleep Disturbances
Terazosin, while structurally similar to prazosin, is not recommended for PTSD-related nightmares and insomnia—prazosin is the alpha-1 antagonist of choice with established evidence for this indication. 1
Why Prazosin, Not Terazosin
Prazosin is the alpha-1 adrenergic receptor antagonist specifically recommended by the American Academy of Sleep Medicine for PTSD-associated nightmares, with Level A evidence supporting its use when first-line non-pharmacological treatments fail or as an adjunct. 1, 2
Terazosin lacks the clinical trial evidence base that prazosin has accumulated for PTSD-related sleep disturbances—all guideline recommendations and research studies focus exclusively on prazosin for this indication. 1, 3, 4
The pharmacokinetic profile matters: prazosin's central nervous system penetration and receptor selectivity have been studied specifically in the context of PTSD nightmares, whereas terazosin has not been systematically evaluated for this purpose. 5
Evidence Supporting Prazosin Use
Meta-analyses demonstrate that prazosin significantly improves nightmares (SMD = -0.641 to -1.13) and insomnia (SMD = -0.654) in PTSD patients, with the most recent 2025 analysis of 10 RCTs involving 648 patients confirming these benefits. 3, 4, 6
Prazosin shows particular efficacy for nightmare reduction, with effect sizes ranging from -0.75 to -1.13 across multiple meta-analyses, representing clinically meaningful improvements. 4, 6
The 2025 meta-regression revealed an unexpected finding: benzodiazepine co-administration appears to enhance prazosin's efficacy for insomnia and overall PTSD severity, suggesting prazosin may allow for benzodiazepine dose reduction. 3
Practical Dosing Algorithm for Prazosin
Start prazosin at 1 mg at bedtime and gradually increase by 1-2 mg every few days until clinical response is achieved, with an average effective dose of 3 mg for nightmares. 1, 2
Monitor for orthostatic hypotension, particularly during dose titration, as this is the primary adverse effect requiring clinical attention. 2
Continue titration based on nightmare frequency and sleep quality improvement, with some patients requiring higher doses for optimal benefit. 1
Treatment Hierarchy
The American Academy of Sleep Medicine recommends Image Rehearsal Therapy (IRT) as first-line treatment for PTSD-associated nightmares, with 60-72% reductions in nightmare frequency and improved sleep quality. 1
Prazosin should be considered when non-pharmacological interventions are insufficient, unavailable, or as an adjunct to psychological treatments like IRT or Cognitive Behavioral Therapy for Insomnia (CBT-I). 1
Progressive Deep Muscle Relaxation (PDMR) can be taught immediately for rapid symptom relief, reducing nightmare frequency by 80% while other treatments are being initiated. 7
Critical Pitfalls to Avoid
Do not substitute terazosin for prazosin simply because it is available or familiar—the evidence base is specific to prazosin, and extrapolating to other alpha-1 antagonists is not supported by guidelines. 1
Avoid assuming that successful treatment of overall PTSD symptoms will automatically resolve sleep disturbances—60% of patients continue reporting nightmares at least once weekly even after effective PTSD treatment. 7
Do not prescribe clonazepam or venlafaxine for nightmares, as these are ineffective according to American Academy of Sleep Medicine guidelines. 2
Alpha-2 agonists like clonidine should not be used for PTSD-related sleep disturbances due to their sedative effects and lack of evidence for this indication. 7
When Prazosin May Be Less Effective
The largest prazosin trial showed similar reductions in clinical outcomes as previous studies but failed to reach statistical significance due to an unexpectedly large placebo effect, particularly for nightmares. 4
Heterogeneity in study populations (military vs. civilian trauma, baseline symptom severity) may influence treatment response, though meta-analyses still support overall efficacy. 3, 4