What is the recommended dose of midodrine (ProAmatine) for treating hypotension (low blood pressure)?

Midodrine Dosing for Hypotension

The recommended dose of midodrine for treating orthostatic hypotension is 10 mg three times daily, administered during daytime hours when the patient needs to be upright and active. 1

Dosing Schedule and Administration

• Initial dosing:

  • Start with 10 mg three times daily 1
  • For patients with renal impairment: Start with 2.5 mg doses 1
  • Timing: Administer at approximately 4-hour intervals during daytime
    • First dose: Shortly before or upon arising in the morning
    • Second dose: Midday
    • Third dose: Late afternoon (not later than 6 PM)

• Dosing intervals:

  • Standard: Every 4 hours
  • May be given at 3-hour intervals if needed to control symptoms, but not more frequently 1

• Maximum dosing:

  • Maximum single dose: 20 mg (though this causes high rates of supine hypertension in ~45% of patients) 1
  • Maximum daily dose: 30 mg (higher doses have been tolerated but not systematically studied) 1

Monitoring and Adjustments

• Regular monitoring of supine and standing blood pressure is essential 1
• Continue treatment only in patients who show symptomatic improvement during initial treatment 1
• Discontinue if supine blood pressure increases excessively 1

Important Precautions

1. Timing restrictions:

   • Do not administer after the evening meal
   • Do not give less than 4 hours before bedtime
   • These restrictions help reduce the risk of supine hypertension during sleep 1

2. Risk of supine hypertension:

   • Occurs in up to 25% of patients 2
   • Minimize by following proper timing of doses

3. Common side effects:

   • Piloerection (goosebumps)
   • Pruritus (itching)
   • Paresthesias
   • Urinary retention
   • Chills 2

Special Populations

• Elderly patients: No dose modifications necessary based on age 1
• Gender differences: No dose modifications necessary 1
• Renal impairment: Start with 2.5 mg doses and titrate cautiously 1
• Children: Dosing not adequately studied 1

Clinical Evidence

Midodrine has demonstrated efficacy in multiple clinical trials:

• Significantly increases standing systolic blood pressure compared to placebo 3, 4
• Improves orthostatic symptoms including dizziness, lightheadedness, and syncope 3
• Shows dose-dependent response with peak effect at 1 hour after administration 5
• Has a half-life of approximately 4 hours for the active metabolite desglymidodrine 5

Potential Complications

• Urologic adverse effects: May cause increased tone of the vesical sphincter leading to urinary retention, particularly in patients with spinal cord injury 6
• Supine hypertension: Monitor closely, especially when initiating therapy 1
• Drug interactions: Use caution with other α-adrenergic agents, which may aggravate supine hypertension 7

Midodrine is one of the first-line pharmacological treatments for orthostatic hypotension, alongside fludrocortisone, when non-pharmacological measures are insufficient 7.