Prazosin
Unchecked
From Pharmacopedia
More actions
Alpha-1 Adrenergic Antagonist
Prazosin
Minipress
Prazosin is best known in psychiatry as an off-label treatment for PTSD nightmares, it suppresses noradrenergic hyperactivity at night and reduces both nightmare frequency and severity in many patients. Originally an antihypertensive; now more often prescribed in mental health than cardiology. First-dose orthostatic hypotension is well-known, start at 1 mg HS and titrate slowly.
Blood pressure (especially orthostatic) during titration.
First-dose effect: marked orthostatic hypotension within 30–90 min. Take initial dose at bedtime. Rise slowly from supine. Effect on nightmares emerges in 1–3 weeks; titrate by 1–2 mg every few nights as needed.
Clonidine, Guanfacine
Experience
No personal reports yet
No clinical reports yet
Log in to add your own experience.
Problems
No problems yet. Be the first to suggest one.
+ Add a problemTitration strategies
No titration strategies yet. Be the first to suggest one.
Effects
No effects listed yet. Be the first to suggest one.
Pharmacokinetics
Absorption
~60% oral bioavailability.Distribution
Plasma protein binding ~97%.Metabolism
Extensive hepatic metabolism.Elimination
Primarily fecal as metabolites.Interactions
Pharmacogenomic + mechanism interactions
Pharmacokinetic mechanismSubstrate / metabolism relationships from primary literature
FDA Drug Interactions Table: transporter substrate (ABCG2).
Rate this interaction. Reports are anonymous and help curate the page.
Clinical relevance: does this interaction matter in practice?trivialcritical
Mechanism description, if it needs work:
Is this row worth surfacing?
Your own experience with this combination:
Experience (1 a little, 5 a lot)
Outcome (-100 worst, +100 best)
Inferred from pharmacokinetic dataMaterialised by the inference engine; provenance shown per row
Novobiocin inhibits ABCG2 (inhibitor, intensity 70); Prazosin is a substrate of ABCG2 (intensity 70). Derived: Prazosin exposure raised.
Inferred via Enzyme:ABCG2 (exposure raised)
Rate this interaction. Reports are anonymous and help curate the page.
Clinical relevance: does this interaction matter in practice?trivialcritical
Confidence in this inference: is the inferred magnitude sound?overstatedsound
Mechanism description, if it needs work:
Is this row worth surfacing?
Your own experience with this combination:
Experience (1 a little, 5 a lot)
Outcome (-100 worst, +100 best)
Patient experience
No patient-experience reports yet.
Monitoring
Patient counseling
Relevant anecdote
No anecdotes yet. Share a relevant one.
Relevant Literature
No literature entries yet.
Log in to submit relevant literature.
See also
References
Summary
Classes
Alpha-1 Adrenergic Antagonist
Common uses
PTSD nightmares0, Hypertension0, BPH0
Pharmacy
Starting dose
1 mg at bedtime (PTSD nightmares); 1 mg BID–TID (HTN)
Preparations
1, 2, 5 mg caps
US FDA Max
40 mg/d
Pharmacology
Routes
Oral
Onset
30–90 min
Duration
6–8 h
Half-life
2–3 h
Bioavailability
~60%
Pregnancy
Category C
Legal status
Rx-only in US
Purported mechanism
Selective alpha-1 adrenergic receptor antagonist. Lowers peripheral vascular resistance via vasodilation; in the CNS, blunts noradrenergic hyperarousal thought to drive trauma-related nightmares.