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prazosin

Adjunctive therapy • Brands: MINIPRESS

Last reviewed: 2025-12-28

General information

Class: Adjunctive therapy
Common US brands: MINIPRESS
Typical dose range: PTSD nightmares (off label): start 1 mg at bedtime; titrate gradually (often in 1 mg increments) based on nightmare frequency and tolerability.
Therapeutic drug monitoring not routinely recommended.
Last reviewed: 2025-12-28

Dosing & forms

Forms/strengths: Capsules: 1 mg, 2 mg, 5 mg.
Frequency: PTSD nightmares (off label): start 1 mg at bedtime; titrate gradually (often in 1 mg increments) based on nightmare frequency and tolerability.
Typical range: PTSD nightmares (off label): start 1 mg at bedtime; titrate gradually (often in 1 mg increments) based on nightmare frequency and tolerability.

Mechanism (brief)

Alpha-1 adrenergic antagonist; reduces sympathetic tone (vasodilation).

Metabolism & Half‑life

Metabolism: Hepatic
Half‑life: Single-dose range 2–3 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

View labelExact

Monitoring highlights

Check blood pressure (including orthostatic vitals) during initiation and after dose increases; counsel hydration and slow positional changes.
Reassess falls risk and co-prescribed sedatives/antihypertensives; adjust titration speed accordingly.
Define a reassessment milestone for nightmare response; taper and stop if benefit is unclear after an adequate trial.
If doses are missed for several days, restart low and retitrate to reduce first-dose syncope risk.

Sources

Prazosin hydrochloride prescribing information — DailyMed (2025)
Trial of prazosin for post-traumatic stress disorder in military veterans — The New England Journal of Medicine (2018)
Prazosin for treatment of post-traumatic stress disorder — CNS Spectrums (2021)
Treatment Guidelines for PTSD — Journal of Clinical Medicine (2021)