The Weekly Mind Reader: Urinary Retention As a Clozapine Side Effect

by Staff Writer
September 8, 2023 at 10:05 AM UTC

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In the realm of psychiatric pharmacotherapy, understanding the potential adverse effects of medications is crucial for ensuring optimal patient care. Clozapine, an atypical antipsychotic known for its efficacy in treating treatment-resistant schizophrenia, has recently been associated with urinary retention. A new case study in The Primary Care Companion for CNS Disorders explored the clinical implications of this rare yet significant side effect. 

Understanding the Case

The case described a 65-year-old male patient with a complex psychiatric history. Despite previous treatment attempts with risperidone, the patient exhibited persistent agitation, aggressive behavior, and visual hallucinations. Consequently, his care team made the decision to initiate clozapine. However, soon after starting treatment, the patient experienced urinary complications, including decreased urinary output, lower abdominal pain, and worsening retention. Timely intervention and medication adjustments led to the resolution of these symptoms.

Why did this happen? 

Clozapine exerts its therapeutic effects through various pharmacological mechanisms. However, its potent anticholinergic activity can inadvertently lead to urinary retention and subsequent incontinence. Furthermore, the drug’s antiadrenergic properties may affect bladder sphincter tone, impairing the bladder’s ability to empty. The dopamine antagonist activity of clozapine can contribute to an overactive bladder, further exacerbating urinary retention as well. 

Clozapine also causes constipation which increases the risk of urinary woes and often leads to abdominal pain. It’s also worth noting that patients with drug-induced diabetes may be susceptible to polyuria, compounding urinary retention problems.

The case report underscores the significance of recognizing and managing urinary retention as a potential adverse effect of clozapine therapy. Clinicians should remain vigilant in monitoring patients for symptoms. A comprehensive evaluation, including physical assessment and the application of the Adverse Drug Reaction Probability Scale, can aid in determining the likelihood of clozapine-induced urinary retention.

In terms of treatment, dose reduction may be a viable strategy. The case demonstrated that lowering the clozapine dose led to an improvement in urinary retention within a few days. Additionally, adjunctive medications, such as tamsulosin for urinary retention and valproate/topiramate for mood stabilization, may prove beneficial in managing the overall well-being of patients.

Clozapine holds immense therapeutic value for treatment-resistant schizophrenia. However, it’s crucial to be on the lookout for urinary retention as a potential side effect, uncommon as it may be. This case study serves as a reminder of the importance of careful monitoring, timely intervention, and dose adjustments when working with patients receiving clozapine therapy. 


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