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

Recommended Dosage of Midodrine for Orthostatic Hypotension

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

Dosing Schedule and Administration

• Doses should be administered at approximately 4-hour intervals:

  • Shortly before or upon arising in the morning
  • Midday
  • Late afternoon (not later than 6 P.M.)

• If needed to control symptoms, doses may be given at 3-hour intervals, but not more frequently 1

• Important timing considerations:

  • Do not administer after the evening meal
  • Do not give less than 4 hours before bedtime (to reduce risk of supine hypertension during sleep) 1

Dosage Adjustments

• Starting dose considerations:

  • For patients with abnormal renal function: Start with 2.5 mg doses due to renal excretion of desglymidodrine (active metabolite) 1
  • No dose modifications needed based on age (≥65) or gender 1

• Maximum dosing:

  • Total daily doses greater than 30 mg have been tolerated by some patients, but safety and efficacy have not been systematically established 1
  • Single doses as high as 20 mg have been given but cause severe and persistent supine hypertension at a high rate (approximately 45%) 1

Monitoring and Follow-up

• Regular monitoring of supine and standing blood pressure is essential 2

  • Continue midodrine only in patients who show symptomatic improvement during initial treatment
  • Stop administration if supine blood pressure increases excessively 1

• The primary therapeutic goal is to minimize postural symptoms rather than restore normotension 2

Clinical Efficacy

• Midodrine increases standing systolic blood pressure by approximately 15-30 mmHg at 1 hour after a 10 mg dose, with effects persisting for 2-3 hours 1

• The 10 mg dose has been shown to significantly improve symptoms of orthostatic hypotension including dizziness, lightheadedness, weakness, and syncope 3, 4

• Studies demonstrate that the 10 mg dose provides optimal balance between efficacy and side effects 4

Common Side Effects

• Piloerection (goosebumps)/scalp tingling (most common)
• Supine hypertension (8%)
• Urinary urgency or retention (4%)
• Gastrointestinal disorders 5, 6

Important Precautions

• Midodrine is contraindicated in patients with severe cardiac disease, acute renal disease, urinary retention, pheochromocytoma, or thyrotoxicosis
• Supine hypertension is a significant risk, especially at higher doses
• The medication should be discontinued if supine hypertension becomes problematic 1

Pharmacokinetics

• Midodrine is a prodrug that is rapidly absorbed and converted to its active metabolite, desglymidodrine
• Peak plasma levels of midodrine occur after about 30 minutes, with a half-life of approximately 25 minutes
• The active metabolite reaches peak concentration 1-2 hours after dosing with a half-life of 3-4 hours 1