From the Guidelines
Botox (onabotulinumtoxinA) for overactive bladder can cause several side effects, with urinary retention being a significant concern, affecting up to 20.49% of patients, as reported in a meta-analysis by Li et al. 1. The most common side effects of Botox for overactive bladder include:
- Urinary tract infection, affecting about 18% of patients
- Urinary retention, where patients have difficulty emptying their bladder completely, occurring in approximately 6% to 20.49% of patients and may require temporary self-catheterization
- Painful urination (dysuria)
- Blood in the urine (hematuria)
- Fatigue Some patients experience flu-like symptoms, headache, or injection site pain. Less commonly, patients may develop bladder pain or experience allergic reactions.
Important Considerations
According to the AUA/SUFU guideline on the diagnosis and treatment of idiopathic overactive bladder, clinicians should measure post-void residual in patients with OAB prior to intradetrusor botulinum toxin therapy and counsel them about the risk of incomplete bladder emptying 1. Additionally, patients should be evaluated approximately 2 weeks after the initial BTX injection to assess symptom improvement and to rule out potential urinary retention, as stated in the guideline 1. It is essential for clinicians to discuss the specific risks of urinary retention and the potential need for intermittent catheterization prior to selecting botulinum toxin therapy, as highlighted in the guideline on adult neurogenic lower urinary tract dysfunction: treatment and follow-up 1.
Treatment and Follow-up
Botox works by temporarily paralyzing the bladder muscle, reducing the involuntary contractions that cause urgency, frequency, and incontinence. The treatment involves injecting small amounts of Botox directly into the bladder wall during a cystoscopy procedure, with effects lasting approximately 6-9 months before retreatment is needed. Patients should report any severe or persistent side effects to their healthcare provider promptly.
From the Research
Side Effects of Botox for Overactive Bladder (OAB)
- The adverse effects of botulinum toxin A, such as urinary retention and urinary tract infection, were primarily localized to the lower urinary tract 2.
- Difficulties in emptying the bladder were observed in some patients who had to resort to periodic self-catheterization for 2-20 weeks 3.
- Side-effects include an increase in post-void residual volume, dysuria and urinary infections 4.
- The use of Botox for OAB has been found to be effective, but it can cause some side effects, and its therapeutic duration can vary 5.
Common Side Effects
- Urinary retention
- Urinary tract infection
- Difficulties in emptying the bladder
- Increase in post-void residual volume
- Dysuria
- Urinary infections
Therapeutic Effects and Duration
- Botox has been found to have sensory inhibitory effects and anti-inflammatory effects, and it has been used to treat OAB and interstitial cystitis/bladder pain syndrome (IC/BPS) 5.
- The therapeutic duration of Botox for OAB can be longer with repeated injections than with a single injection 5.
- Botox has been found to be an effective treatment for patients with refractory idiopathic or neurogenic detrusor overactivity, with improvements in urinary incontinence episodes, maximum cystometric capacity, and maximum detrusor pressure 2.