Is it feasible to discontinue Flomax (Tamsulosin) and start Midodrine in a patient with End-Stage Renal Disease (ESRD) on Hemodialysis (HD) with orthostatic hypotension?

From the Guidelines

Yes, it is feasible to discontinue Flomax and start Midodrine for a patient with end-stage renal disease (ESRD) on hemodialysis (HD) who has orthostatic hypotension, as Midodrine is specifically indicated for orthostatic hypotension, while Flomax is an alpha-1 blocker used primarily for benign prostatic hyperplasia that can actually worsen hypotension 1. The typical starting dose of Midodrine is 2.5 mg three times daily, with doses given upon waking, at midday, and in the late afternoon (no later than 6 PM to avoid supine hypertension during sleep). Some key points to consider when making this medication change include:

• Flomax should be tapered rather than abruptly discontinued to avoid rebound symptoms
• Monitor the patient's blood pressure in both supine and standing positions during the transition
• Midodrine is generally well-tolerated in ESRD patients and does not require dose adjustment for renal impairment
• The medication works by activating alpha-1 receptors, causing arterial and venous constriction, which increases blood pressure and improves orthostatic symptoms like dizziness and syncope 1. Additionally, nonpharmacologic measures such as ensuring adequate salt intake, avoiding medications that aggravate hypotension, and using compressive garments over the legs and abdomen can be used in conjunction with Midodrine to manage orthostatic hypotension 1. It is also important to note that physical activity and exercise should be encouraged to avoid deconditioning, which is known to exacerbate orthostatic intolerance, and volume repletion with fluids and salt is critical 1.

From the FDA Drug Label

Midodrine use has not been studied in patients with renal impairment Because desglymidodrine is eliminated via the kidneys, and higher blood levels would be expected in such patients, midodrine should be used with caution in patients with renal impairment, with a starting dose of 2.5 mg [seeDOSAGE AND ADMINISTRATION]. A study with 16 patients undergoing hemodialysis demonstrated that midodrine is removed by dialysis.

Discontinuing Flomax and starting Midodrine in a patient with ESRD on HD with orthostatic hypotension is not straightforward.

• The patient's renal impairment and hemodialysis treatment should be taken into consideration when using midodrine, as its metabolite is eliminated via the kidneys and may accumulate in patients with renal impairment.
• Caution is advised when using midodrine in patients with renal impairment, and a starting dose of 2.5 mg is recommended.
• Additionally, the fact that midodrine is removed by dialysis should be considered when determining the dosing schedule for a patient undergoing hemodialysis.
• No direct information is available on the safety and efficacy of switching from Flomax to midodrine in patients with ESRD on HD with orthostatic hypotension 2 2.

From the Research

Discontinuing Flomax and Starting Midodrine for a Patient with ESRD on HD

• The patient has orthostatic hypotension and is currently on Flomax, but it is being considered to discontinue Flomax and start Midodrine.
• Midodrine has been shown to be effective in treating intradialytic hypotension in patients with end-stage renal disease (ESRD) 3.
• A study published in 1997 found that midodrine improved blood pressure and reduced symptoms associated with dialysis hypotension in 10 hemodialysis patients with persistent intradialytic hypotension 3.
• Another study published in 2017 discussed the use of midodrine for hypotension outside of the intensive care unit, including its use in patients with ESRD 4.
• However, there is a case report of midodrine-induced vascular ischemia in a hemodialysis patient, highlighting the potential risks of using midodrine in patients with ESRD 5.

Considerations for Discontinuing Flomax

• Flomax (tamsulosin) is an alpha-blocker that can cause orthostatic hypotension as a side effect.
• Discontinuing Flomax may help alleviate orthostatic hypotension, but it is essential to consider the patient's individual response to the medication and the potential impact on their overall health.
• There is limited information available on the use of fludrocortisone for orthostatic hypotension, and the evidence is very uncertain about its effects on blood pressure, orthostatic symptoms, or adverse events 6.

Potential Benefits and Risks of Starting Midodrine

• Midodrine may be beneficial in treating orthostatic hypotension in patients with ESRD, but it is crucial to weigh the potential benefits against the risks, including the possibility of midodrine-induced vascular ischemia 5.
• The patient's individual response to midodrine and their overall health status should be carefully considered before starting the medication.
• It is essential to monitor the patient's blood pressure and adjust the midodrine dosage as needed to minimize the risk of adverse effects 3, 4.