What is the recommended dose of midodrine (ProAmatine) for treating orthostatic hypotension?

Recommended Dosage of Midodrine for Orthostatic Hypotension

The recommended dosage of midodrine for treating orthostatic hypotension is 10 mg three times daily, administered during daytime hours when the patient needs to be upright, with doses spaced approximately 4 hours apart. 1

Dosing Schedule and Administration

• Initial dosing:

  • Start with 2.5 mg three times daily for patients with renal impairment 1
  • Standard starting dose is 10 mg three times daily 1

• Timing of administration:

  • First dose: Shortly before or upon arising in the morning
  • Second dose: Midday
  • Third dose: Late afternoon (not later than 6 PM) 1
  • Doses should be at least 3-4 hours apart 1
  • Last dose should not be taken after the evening meal or less than 4 hours before bedtime to reduce the risk of supine hypertension 1

• Dose adjustments:

  • Doses may be given in 3-hour intervals if required to control symptoms, but not more frequently 1
  • Maximum daily dose should not exceed 30 mg 1
  • Single doses as high as 20 mg have been given but are associated with a high rate (45%) of severe and persistent supine hypertension 1

Special Populations

• Renal impairment: Start with 2.5 mg doses and titrate cautiously 1
• Elderly patients: No dose modifications necessary based on age 1
• Gender differences: No dose modifications necessary based on gender 1

Monitoring and Safety Considerations

• Blood pressure monitoring:

  • Regular monitoring of supine and standing blood pressure is essential 2
  • Discontinue treatment if supine blood pressure increases excessively 1
  • Continue only in patients who show symptomatic improvement during initial treatment 1

• Common side effects:

  • Supine hypertension (8%) 3
  • Scalp pruritus/tingling (13.5%) 3
  • Urinary urgency or retention (4%) 3
  • Piloerector reactions 4

Clinical Evidence and Efficacy

• Midodrine significantly increases standing systolic blood pressure, with peak effect occurring at 1 hour post-dose 5
• The half-life of the active metabolite (desglymidodrine) is approximately 4 hours, supporting the three-times-daily dosing regimen 5
• In clinical trials, 10 mg three times daily increased standing systolic blood pressure by 22 mmHg (28%) compared to placebo 3
• Midodrine has been shown to improve symptoms of orthostatic hypotension including dizziness, lightheadedness, weakness, fatigue, and syncope 4, 3

Important Cautions

• Midodrine should not be used in patients with severe cardiac disease, acute renal disease, urinary retention, pheochromocytoma, or thyrotoxicosis
• The medication may be poorly tolerated in patients with heart failure 6
• For patients with cardiac amyloidosis and severe autonomic dysfunction, orthostatic hypotension requiring medications like midodrine that cannot be weaned may be a contraindication to heart transplantation 6

Remember that the therapeutic goal is to minimize postural symptoms rather than restore normotension 2. Regular follow-up is essential to assess treatment effectiveness and monitor for supine hypertension.