What medications are suitable for a patient with bipolar disorder and urinary retention?

Medication Selection for Bipolar Disorder in Patients with Urinary Retention

For patients with bipolar disorder and urinary retention, beta-3 agonists (mirabegron) combined with mood stabilizers are the preferred treatment approach, while anticholinergic medications should be avoided due to their high risk of worsening urinary retention. 1

Medication Considerations for Urinary Retention

Medications to Avoid

• Anticholinergic medications: These significantly increase the risk of urinary retention and should be avoided in patients with existing urinary retention:
  • Tricyclic antidepressants (especially imipramine with 17.6% risk of urinary retention) 2
  • Typical antipsychotics with high anticholinergic properties 2
  • Antimuscarinic agents 1

Preferred Medications for Bipolar Disorder with Urinary Retention

First-Line Options:

1. Mood stabilizers:

   • Lithium - remains the cornerstone of maintenance therapy for bipolar disorder 3
   • Valproate - effective alternative with less impact on urinary function 3
   • Lamotrigine - particularly effective for bipolar depression with minimal urinary side effects 3

2. Atypical antipsychotics with lower anticholinergic burden:

   • Aripiprazole - indicated as an adjunct to lithium or valproate for maintenance treatment of bipolar disorder 4
   • Consider avoiding ziprasidone as it has been associated with urinary retention (1 in 21 patients) 2

Treatment Algorithm

Step 1: Initial Treatment

• Begin with a non-anticholinergic mood stabilizer:
  • Lithium (first choice if no contraindications)
  • Valproate (alternative if lithium is contraindicated)
  • Lamotrigine (especially if depression predominates)

Step 2: For Inadequate Response

• Add an atypical antipsychotic with low anticholinergic properties:
  • Aripiprazole as adjunct to lithium or valproate 4

Step 3: For Patients with Concurrent Storage Symptoms

• Consider adding mirabegron (beta-3 agonist) which has been shown to be safe in patients with urinary retention 1
  • Mirabegron add-on therapy has demonstrated efficacy and safety in patients with lower urinary tract symptoms 1

Step 4: Monitoring

• Regularly assess post-void residual urine volume
• Monitor for worsening urinary symptoms, especially when initiating or changing medications
• Adjust medication doses based on both psychiatric response and urinary function

Special Considerations

For Acute Manic Episodes

• If rapid tranquilization is needed, avoid high-dose anticholinergic antipsychotics
• Consider aripiprazole which is indicated for acute treatment of manic or mixed episodes 4

For Bipolar Depression

• Lamotrigine may be preferred due to its efficacy in bipolar depression and minimal impact on urinary function 3
• Avoid tricyclic antidepressants completely (high risk of urinary retention) 2
• SSRIs have lower risk (0.025%) but should still be used cautiously 2

For Maintenance Therapy

• Combination therapy is often necessary for optimal management 5
• Effective combinations with minimal urinary impact include:
  • Lithium + lamotrigine
  • Mood stabilizer + aripiprazole

Important Caveats

• PVR measurements are recommended during treatment, especially if adding any medication with potential urinary effects 1
• Patients with urinary retention should not receive antimuscarinic medications if PVR volume exceeds 150 ml 1
• Most patients with bipolar I disorder will require ongoing medication therapy to prevent relapse 5
• The risk of urinary retention is higher in elderly patients and those with benign prostatic hyperplasia 6

By following this algorithm and carefully selecting medications with minimal impact on urinary function, patients with bipolar disorder and urinary retention can achieve symptom control while minimizing the risk of worsening urinary symptoms.