From the Guidelines
Oxybutynin should only be considered as a second-line treatment for nocturnal enuresis in children who have failed standard treatment, due to its potential side effects and the need for careful patient selection. The use of oxybutynin in treating nocturnal enuresis is supported by a study published in The Journal of Urology in 2010 1, which suggests that anticholinergic drugs like oxybutynin can suppress detrusor overactivity, which may be present in children with monosymptomatic enuresis.
Some key points to consider when using oxybutynin for nocturnal enuresis include:
- The institution of sound, regular voiding habits should be tried first
- Constipation should be excluded or treated
- Post-void residual urine, dysfunctional voiding, or low voiding frequency should be excluded
- A frequency-volume chart should be completed and uroflowmetry with ultrasound measurement of post-void residual urine should be performed
The usual dose of oxybutynin is 5 mg at bedtime, which may need to be doubled in some cases 1. The anti-enuretic effect should appear within a maximum of 2 months, and combination treatment with desmopressin may be needed. Common side effects of oxybutynin include constipation, which may be heralded by a slowly decreasing anti-enuretic effect, and the risk of mood changes, although this seems to be uncommon when alternatives other than oxybutynin are chosen 1.
It is essential to monitor the child's response to oxybutynin and adjust the treatment as needed to minimize side effects and maximize efficacy. Regular follow-up is crucial to assess the effectiveness of the treatment and manage any potential side effects.
From the FDA Drug Label
INDICATIONS AND USAGE Oxybutynin chloride is indicated for the relief of symptoms of bladder instability associated with voiding in patients with uninhibited neurogenic or reflex neurogenic bladder (i.e., urgency, frequency, urinary leakage, urge incontinence, dysuria). The FDA drug label does not answer the question.
From the Research
Role of Oxybutynin in Treating Nocturnal Enuresis
Oxybutynin is an antimuscarinic agent that has been used in combination with desmopressin to treat nocturnal enuresis. The following points highlight its role:
- Oxybutynin allows the bladder to store more urine, reducing the likelihood of nocturnal enuresis 2.
- Combination therapy with desmopressin and oxybutynin has been shown to be effective in treating monosymptomatic nocturnal enuresis (MNE) 2, 3, 4.
- Studies have demonstrated that the addition of oxybutynin to desmopressin therapy can improve response rates in patients with MNE 2, 3.
Comparison with Desmopressin
Comparisons between oxybutynin and desmopressin have been made in several studies:
- Desmopressin has been shown to be more effective than oxybutynin in reducing the frequency of nocturnal enuresis 5.
- Oxybutynin has been associated with more side effects, such as constipation and xerostomia, compared to desmopressin 5.
- Combination therapy with desmopressin and oxybutynin may be recommended for specially selected cases 2.
Predictors of Response to Combination Therapy
Certain factors have been identified as predictors of response to combination therapy with desmopressin and oxybutynin:
- Nocturnal polyuria (NP) has been shown to be a significant predictor of response to combination therapy 3.
- Absence of constipation has also been identified as a predictor of response to combination therapy 3.
Patient Selection
Patient selection is crucial when considering oxybutynin therapy for nocturnal enuresis: