Can fluoxetine (selective serotonin reuptake inhibitor) cause dysuria (painful urination)?

Fluoxetine and Dysuria: A Recognized Adverse Effect

Yes, fluoxetine can cause dysuria (painful urination) as a rare but documented adverse effect related to its serotonergic properties that affect urinary tract function.

Mechanism and Evidence

Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), can affect urinary function through several mechanisms:

1. Serotonergic Effects on Urinary Function:

   • Serotonin plays a role in regulating bladder function and micturition
   • Fluoxetine's enhancement of serotonergic transmission can alter normal urinary tract function

2. Documented Cases:

   • Recent case reports have documented urinary retention associated with fluoxetine use 1
   • A 2022 case report described a 15-year-old girl who developed chronic urinary retention during fluoxetine monotherapy, which resolved after discontinuation of the medication 1

3. Pharmacological Interactions:

   • Fluoxetine's pharmacokinetic properties, particularly its inhibition of CYP2D6, may contribute to urinary side effects 2
   • When combined with other medications, the risk may increase, as seen in a case of urinary retention after fluoxetine-risperidone combination 3

Risk Factors and Presentation

Patients at higher risk for fluoxetine-related dysuria include:

• Those with pre-existing genitourinary conditions
• Older adults (who are more susceptible to anticholinergic effects)
• Patients taking multiple medications that affect urinary function
• Those on higher doses of fluoxetine

Symptoms may present as:

• Painful urination (dysuria)
• Difficulty initiating urination
• Sensation of incomplete bladder emptying
• In severe cases, urinary retention requiring intervention

Management Approach

When dysuria occurs in a patient taking fluoxetine:

1. Assess Causality:

   • Rule out other common causes of dysuria (UTI, prostatitis, etc.)
   • Consider timing of symptom onset in relation to fluoxetine initiation or dose changes

2. Intervention Options:

   • Dose Reduction: Consider lowering the dose if clinically appropriate
   • Medication Switch: If symptoms persist, consider switching to another antidepressant with lower incidence of urinary side effects
   • Discontinuation: In severe cases, discontinuation of fluoxetine may be necessary, as demonstrated in case reports where symptoms resolved after stopping the medication 1

3. Monitoring:

   • Monitor for resolution of symptoms after intervention
   • Watch for signs of urinary retention, which can be a more serious complication

Clinical Considerations

• The American Family Physician notes that SSRIs, including fluoxetine, can cause various adverse effects, though urinary symptoms are not among the most common 2
• When selecting antidepressants for older patients who may be more susceptible to urinary side effects, citalopram, escitalopram, sertraline, mirtazapine, venlafaxine, and bupropion are generally preferred over fluoxetine 2
• Fluoxetine is metabolized by CYP2D6, and genetic variations in this enzyme may affect drug metabolism and potentially increase the risk of adverse effects 2

Conclusion

While not among the most commonly reported side effects, dysuria can occur with fluoxetine use. The evidence from case reports demonstrates a clear temporal relationship between fluoxetine administration and urinary symptoms, with resolution upon discontinuation. Clinicians should be aware of this potential adverse effect when prescribing fluoxetine and monitor patients accordingly, especially those with pre-existing urinary tract conditions.