Can Guanfacine Cause Bedwetting?
No, guanfacine does not cause bedwetting (nocturnal enuresis) and may actually improve it in some patients with ADHD who also have enuresis.
Evidence from FDA Drug Labeling
The FDA-approved drug label for guanfacine lists urinary incontinence as a reported adverse effect, but this occurred in ≤3% of patients in controlled trials and was not specifically nocturnal enuresis 1. The label also mentions nocturia (nighttime urination) and urinary frequency as rare adverse events in postmarketing surveillance, but these are distinct from bedwetting 1.
Key distinction: Urinary incontinence in the FDA label refers to daytime loss of bladder control in adults with hypertension, not nocturnal enuresis in children.
Clinical Context from Guidelines
The 2019 ADHD guidelines note that guanfacine's adverse effects include somnolence, dry mouth, dizziness, irritability, headache, bradycardia, hypotension, and abdominal pain—but enuresis is not listed among the recognized side effects 2.
The 2010 enuresis guidelines make no mention of guanfacine causing or worsening bedwetting 3.
Emerging Evidence of Therapeutic Benefit
Contrary to causing enuresis, there is a 2022 case report demonstrating that guanfacine monotherapy (1 mg/day) successfully treated nocturnal enuresis in a 10-year-old girl with ADHD 4. This suggests guanfacine may have a beneficial effect on enuresis in children with comorbid ADHD, though this is based on limited evidence.
Clinical Recommendation
If a patient on guanfacine develops new-onset bedwetting:
- Consider alternative causes (urinary tract infection, diabetes, constipation, sleep apnea, psychological stress)
- Review timing: Did enuresis begin after starting guanfacine or was it pre-existing?
- Evaluate for excessive somnolence from guanfacine, which could impair arousal from sleep when bladder is full
- Consider that the ADHD itself (not the medication) may be associated with enuresis, as approximately 30% of children with ADHD have nocturnal enuresis 4
Bottom line: Guanfacine is not recognized as a cause of bedwetting in authoritative sources. The rare reports of urinary incontinence in FDA labeling refer to a different phenomenon in adults. If enuresis occurs during guanfacine treatment, investigate other causes rather than automatically attributing it to the medication.