Prazosin
Minipress
Alpha-1 Adrenergic BlockerGeneric available
Clinical Pharmacology The exact mechanism of the hypotensive action of prazosin is unknown. Prazosin causes a decrease in total peripheral resistance and was originally thought to have a direct relaxant action on vascular smooth muscle. Recent animal studies, however, have suggested that the vasodilator effect of prazosin is also related to blockade of postsynaptic alpha-adrenoceptors.
Compare Prazosin →FDA-Approved Indications
- Hypertension (adults)
Common Off-Label Uses
- PTSD nightmares
- Benign prostatic hyperplasia
- Raynaud's phenomenon
What Sets This Drug Apart
- Alpha-1 antagonist; FDA-approved for hypertension but primarily used off-label for PTSD nightmares and trauma-related sleep disturbance
- Only pharmacotherapy with randomized evidence for PTSD-associated nightmares — a unique clinical niche
- Orthostatic hypotension is early and pronounced; first-dose syncope possible — start very low (0.5-1 mg HS) and titrate slowly
- Short half-life (2-3h) means nighttime-only dosing is typical for PTSD; daytime hyperarousal may require BID-TID dosing
- Typical PTSD nightmare dose range is 5-15 mg HS, much higher than hypertension doses; full benefit takes 2-4 weeks