Can midodrine (midodrine) be causing burning sensation when voiding in an 87-year-old patient with urinary retention?

Can Midodrine Be Causing Burning Sensation When Voiding in Your 87-Year-Old Patient?

Yes, midodrine can absolutely cause urinary symptoms including burning with urination in your 87-year-old patient, primarily through its alpha-1 adrenergic effects on the bladder neck and urethra leading to urinary retention, which increases infection risk and can produce dysuria. 1, 2

Mechanism of Midodrine-Related Urinary Symptoms

Midodrine's active metabolite, desglymidodrine, acts as an alpha-1 adrenoceptor agonist that increases tone at the bladder neck and throughout the urethra, causing increased outlet resistance and potentially leading to urinary retention 1, 2. This mechanism can produce burning sensations through:

• Direct urinary retention: Alpha-1 stimulation increases vesical sphincter tone, leading to incomplete bladder emptying and progressive urine retention 1, 2
• Secondary urinary tract infection: Retained urine creates an ideal environment for bacterial growth, with elderly patients in long-term care having UTI rates of 25-50% in women and 15-40% in men 3
• Bladder overdistension: Chronic retention can cause bladder wall changes and irritative symptoms including dysuria 2

Clinical Evidence Supporting This Association

The FDA label explicitly warns that "midodrine should be used cautiously in patients with urinary retention problems, as desglymidodrine acts on the alpha-adrenergic receptors of the bladder neck" 1.

Two case reports document the insidious development of urologic adverse effects in patients taking midodrine, where patients developed progressive difficulty voiding, severe leg spasms during urination, and very slow urine flow 2. Notably, these symptoms resolved completely after midodrine discontinuation 2.

Urinary retention is listed as one of the most commonly reported adverse events with midodrine therapy, along with piloerection, pruritus, and paraesthesias 4.

Immediate Diagnostic Steps

Assess for urinary retention first by measuring post-void residual urine volume using bladder ultrasound or straight catheterization 5. This is critical because:

• Elderly men frequently have underlying prostatic hypertrophy causing baseline voiding dysfunction 3
• Urinary retention may be asymptomatic initially, presenting only as dysuria or frequency 3
• Post-void residual >100-150 mL suggests significant retention requiring intervention 5

Obtain urinalysis and urine culture if pyuria is present (≥10 WBCs/high-power field or positive leukocyte esterase) 3. In elderly patients with suspected UTI, diagnostic evaluation should be reserved for those with acute onset of symptoms including dysuria, fever, new incontinence, or suspected bacteremia 3.

Management Algorithm

If Urinary Retention is Confirmed:

1. Discontinue or reduce midodrine dose immediately 1, 2. The FDA label states patients should discontinue medication if problematic symptoms persist 1

2. Initiate bladder decompression via intermittent catheterization rather than indwelling catheter to minimize infection risk 5

3. Consider alpha-blocker therapy (tamsulosin or alfuzosin) to counteract midodrine's alpha-1 agonist effects and facilitate bladder emptying 5. This is standard management for urinary retention, with success rates of 47-60% versus 29-39% for placebo 5

4. Treat any concurrent UTI if culture-positive, as bacteriuria occurs in up to 28% of elderly patients and retention significantly increases this risk 3

If UTI Without Retention:

• Treat the infection with appropriate antibiotics based on culture results 3
• Still consider reducing or discontinuing midodrine, as the drug may have contributed to retention that precipitated the infection 2
• Monitor post-void residuals even after infection resolves 5

Alternative Management for Orthostatic Hypotension

If your patient requires continued treatment for orthostatic hypotension after stopping midodrine:

• Fludrocortisone is an alternative that does not cause urinary retention 2, 4
• Non-pharmacologic measures: Compression stockings, increased fluid/salt intake, sleeping with head elevated 1
• Combination therapy: Lower doses of midodrine (2.5 mg) with fludrocortisone may reduce urologic side effects while maintaining blood pressure control 1, 2

Critical Caveats for This Patient Population

Elderly patients are at particularly high risk for midodrine-related urinary complications because 1, 6:

• Pre-existing benign prostatic hyperplasia in men (prevalence increases substantially after age 60) 3
• Baseline detrusor underactivity common in elderly patients 3
• Polypharmacy with other anticholinergic medications that compound retention risk 6
• Diabetic cystopathy if diabetic (occurs in up to 80% of type 1 diabetics, with impaired detrusor contractions) 3

The urologic effects can develop insidiously over weeks to months, as documented in the case series where symptoms emerged 7 weeks and 3 months after starting midodrine 2. Therefore, even if your patient has been on midodrine for some time without prior issues, it remains a likely culprit.

Do not assume the burning is simply a UTI without assessing retention status, as treating infection alone while continuing midodrine will likely result in recurrent symptoms 2.