What is the maximum recommended dose of extended‑release prazosin (Minipress XL)?

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Maximum Dose of Prazosin XL

The maximum dose of extended-release prazosin (Minipress XL) is 20 mg once daily, as established in clinical trials for hypertension. 1

Standard Maximum Dosing by Indication

For Hypertension (Extended-Release Formulation)

  • Minipress XL has a maximum approved dose of 20 mg once daily when used for mild to moderate essential hypertension 1
  • The extended-release formulation was studied at doses of 10 mg and 20 mg once daily, with both doses demonstrating efficacy and safety 1
  • The American College of Cardiology recommends standard prazosin (immediate-release) at 2-20 mg per day in 2-3 divided doses for hypertension with concomitant BPH 2

For PTSD-Related Nightmares (Immediate-Release)

  • The American Academy of Sleep Medicine reports that prazosin was escalated to a maximum of 20 mg as a single bedtime dose in large VA studies for PTSD-related nightmares 2
  • Mean achieved doses in military veterans ranged from 14.8-15.6 mg for men and 7.0 mg for women, all below the 20 mg maximum 2
  • Target doses are typically 3-4 mg/day for civilians or 9.5-15.6 mg/day for military veterans 3

Important Clinical Context

The 20 mg maximum applies specifically to the extended-release formulation (Minipress XL) given once daily. 1 This differs from immediate-release prazosin, which requires 2-3 times daily dosing and has the same 20 mg total daily maximum but divided across multiple doses. 2

Higher Doses in Case Reports

  • Case reports have described prazosin doses up to 30-45 mg daily for treatment-resistant PTSD, though these exceed standard recommendations and are not part of routine practice 4
  • The highest reported dose in systematic studies remains 20 mg daily 5

Safety Considerations

  • Start at 1 mg at bedtime to minimize first-dose orthostatic hypotension 6, 3
  • Titrate by 1-2 mg every few days until clinical response 3
  • Monitor blood pressure after the initial dose and with each significant dose increase 3
  • Elderly patients are more susceptible to orthostatic hypotension and require careful blood pressure monitoring 2

References

2
Guideline

Prazosin Dosing Guidelines

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

3
Guideline

Prazosin for Vivid Craving or Using Dreams in Substance Use Recovery

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

4
Research

High-dose prazosin for the treatment of post-traumatic stress disorder.

Therapeutic advances in psychopharmacology, 2014

6
Guideline

Clinical Use of Prazosin

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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