Midodrine Dosing for Orthostatic Hypotension
The recommended dosing for midodrine for orthostatic hypotension is 10 mg three times daily, administered during daytime hours when the patient needs to be upright and active. 1
Standard Dosing Protocol
- Initial dose: 10 mg three times daily
- Timing: Administer at approximately 4-hour intervals:
- Upon arising in the morning
- Midday
- Late afternoon (not later than 6 PM)
- Maximum daily dose: 30 mg (10 mg × 3 doses)
- Alternative interval: Doses may be given at 3-hour intervals if needed to control symptoms, but not more frequently 1
Dosing Considerations
Special Populations
- Renal impairment: Start with 2.5 mg doses in patients with abnormal renal function 1
- Elderly patients: No dose adjustment necessary based on age 1
- Gender: No dose adjustment necessary based on gender 1
Titration
While the FDA-approved dose is 10 mg three times daily, clinical studies have shown:
- Single doses as high as 20 mg have been used but cause severe supine hypertension in about 45% of patients 1
- Some patients may respond to lower doses (5 mg) particularly those with diabetic autonomic neuropathy 2, 3
Administration Guidelines
Critical Timing Considerations
- Do not administer after the evening meal
- Do not administer less than 4 hours before bedtime
- These restrictions help reduce the risk of supine hypertension during sleep 1
Monitoring Requirements
- Regular monitoring of supine and standing blood pressure is essential
- Discontinue treatment if supine blood pressure increases excessively 1
- Continue only in patients who demonstrate symptomatic improvement during initial treatment 1
Efficacy
Midodrine at 10 mg three times daily has been shown to:
- Increase standing systolic blood pressure by approximately 22 mmHg (28%) 4
- Significantly improve symptoms of orthostatic hypotension including dizziness, lightheadedness, weakness, fatigue, and syncope 4, 5
- Peak effect occurs approximately 1 hour after administration 3
- Duration of action is approximately 4 hours, consistent with the half-life of the active metabolite desglymidodrine 3
Common Side Effects
- Piloerection (goosebumps)
- Scalp itching or tingling (reported in 13.5% of patients)
- Supine hypertension (8% of patients)
- Urinary urgency or retention (4% of patients)
- Nausea, heartburn, headache, nervousness, and sleep disturbance 6, 4
Important Cautions
- Supine hypertension is a significant concern with midodrine therapy
- The medication should be continued only in patients who demonstrate symptomatic improvement
- Patients with pre-existing cardiac disease or risk factors for atrial fibrillation require careful monitoring 6
- Use cautiously in patients with end-stage renal disease, as it may be associated with higher risks of cardiovascular events 6