What is the role of midodrine in managing hypotension in dialysis patients?

From the Guidelines

Midodrine is a recommended medication for managing hypotension in dialysis patients, as it has been shown to minimize intradialytic hypotensive events and raise the lowest intradialytic blood pressure. The medication works as an alpha-1 adrenergic agonist that increases peripheral vascular resistance and blood pressure by causing vasoconstriction 1.

Key Points

• The typical dosing regimen is 5-10 mg taken 30 minutes before dialysis sessions, with some patients requiring up to 10 mg three times daily 1.
• Midodrine is particularly useful for patients who experience symptomatic hypotension during dialysis despite other interventions like adjusting dry weight, reducing ultrafiltration rates, or increasing dialysate sodium concentration.
• Common side effects include piloerection (goosebumps), scalp tingling, and supine hypertension, which is why patients should remain upright for at least 4 hours after taking the medication 1.
• Patients with severe heart disease, acute kidney injury, urinary retention, or pheochromocytoma should avoid midodrine due to potential complications.

Administration and Monitoring

• Midodrine should be used cautiously in patients with CHF and in those using other negative chronotropic agents such as beta-blockers, digoxin and nondihydropyridine CCBs 1.
• Concomitant use with other-adrenergic agents—such as ephedrine, pseudoephedrine and phenylpropanolamine—should be avoided, as this may aggravate supine hypertension.
• The combination of cool dialysate and predialysis doses of midodrine may lead to decreased frequency and intensity of symptoms of IDH without side effects 1.

From the FDA Drug Label

Midodrine has been studied in 3 principal controlled trials, one of 3-weeks duration and 2 of 1 to 2 days duration. All studies were randomized, double-blind and parallel-design trials in patients with orthostatic hypotension of any etiology and supine-to-standing fall of systolic blood pressure of at least 15 mmHg accompanied by at least moderate dizziness/lightheadedness A study with 16 patients undergoing hemodialysis demonstrated that midodrine is removed by dialysis.

The role of midodrine in managing hypotension in dialysis patients is to increase blood pressure. Midodrine is an alpha1-agonist that exerts its actions via activation of the alpha-adrenergic receptors of the arteriolar and venous vasculature, producing an increase in vascular tone and elevation of blood pressure. However, it is removed by dialysis, which may affect its efficacy in this patient population. Key points to consider:

• Efficacy: Midodrine increases standing systolic blood pressure in patients with orthostatic hypotension.
• Dialysis: Midodrine is removed by dialysis, which may impact its effectiveness in dialysis patients.
• Dosage: The typical dose of midodrine is 10 mg t.i.d., with the last dose not later than 6 P.M. 2

From the Research

Role of Midodrine in Managing Hypotension in Dialysis Patients

• Midodrine is a selective alpha-1 adrenergic pressor agent used to treat hypotension in dialysis patients 3.
• A study published in 1996 found that midodrine significantly increased the mean minimal systolic pressure and elevated the mean diastolic pressure during hemodialysis, with no apparent clinical or laboratory abnormalities observed 3.
• Another study published in 2003 demonstrated the efficacy and safety of midodrine in the treatment of dialysis-associated hypotension, with midodrine reducing the severity and frequency of hypotensive episodes in patients 4.

Comparison with Other Treatments

• A case report published in 2018 found that fludrocortisone may be helpful for the treatment of intradialytic hypotension that does not respond to midodrine administration 5.
• A review published in 1998 found that midodrine has similar efficacy to other treatments such as dihydroergotamine mesylate, norfenefrine, fludrocortisone, and etilefrine, and is more effective than dimetofrine and ephedrine in patients with orthostatic hypotension 6.

Clinical and Hemodynamic Outcomes

• A study published in 2018 found that midodrine use was associated with higher rates of death, all-cause hospitalization, and cardiovascular hospitalization, and tended to be associated with lower pre-dialysis systolic blood pressure and greater fall in systolic blood pressure during dialysis 7.
• However, another study published in 1996 found that midodrine increased the mean minimal systolic pressure and elevated the mean diastolic pressure during hemodialysis, suggesting a potential beneficial effect on hemodynamic outcomes 3.