Overactive Bladder (OAB)

What overactive bladder is

Normally, the bladder fills quietly and you feel a gradual need to urinate that you can postpone. In OAB, the bladder sends sudden, strong signals to empty, often when it is not full. The bladder muscle (detrusor) may contract involuntarily. OAB is a symptom syndrome, defined by urgency, usually with:

• frequency: urinating 8 or more times in 24 hours
• nocturia: waking 1 or more times at night to urinate
• urge incontinence: leaking with urgency, in "OAB wet"

"OAB dry" means urgency without leakage.

Symptoms

• sudden, compelling urges that are hard to delay
• needing to urinate very often, often small amounts
• waking at night to urinate
• leaking on the way to the toilet
• "key in the door" or "running water" urgency triggers
• planning life around toilets and avoiding activities

Causes and risk factors

Most OAB has no single identifiable cause. Contributing factors include:

• age
• neurological conditions: stroke, Parkinson's disease, multiple sclerosis, spinal cord injury, dementia
• enlarged prostate in men, which can cause urgency alongside weak flow
• menopause: low estrogen affects the bladder and urethra. See atrophic vaginitis
• obesity
• diabetes, which also increases urine production
• caffeine, alcohol and fizzy drinks
• constipation, which presses on the bladder
• anxiety
• medicines: diuretics

Conditions that mimic OAB

Diagnosis

• history of symptoms and their impact, fluids, medicines and other conditions
• bladder diary for 3 days: times and volumes of drinks and urination, leaks and urgency
• urine test for infection and blood
• physical exam, including pelvic exam in women and prostate exam in men
• post-void residual: a bladder scan after urinating to check emptying
• urodynamic tests and cystoscopy only for complex cases, before invasive treatment, or with blood in the urine

Treatment

The 2024 AUA/SUFU guideline encourages offering all options, chosen by the patient's preference, rather than a strict step ladder.

Behavioral treatments

• bladder training: gradually increase the time between bathroom trips, using urge-suppression techniques such as standing still, squeezing the pelvic floor quickly several times and breathing until the urge passes
• timed voiding
• pelvic floor muscle training, ideally with a pelvic floor physical therapist
• fluid management: about 6 to 8 cups (1.5 to 2 liters) a day, spread out, and less in the evening
• cut back on caffeine, alcohol and fizzy drinks
• weight loss if overweight
• treat constipation

Medicines

• Beta-3 agonists: mirabegron and vibegron relax the bladder muscle with fewer side effects such as dry mouth. They are often preferred in older adults
• Antimuscarinics: oxybutynin, tolterodine, solifenacin, trospium and others. Side effects include dry mouth, constipation and blurred vision. Long-term use of strongly anticholinergic drugs is linked to cognitive decline and dementia risk in older adults, so guidelines advise caution
• Vaginal estrogen for postmenopausal women with urinary symptoms
• Combination therapy for those not responding to one medicine

Advanced treatments

• Botulinum toxin (Botox) bladder injections: given through a cystoscope, lasting about 6 to 12 months. A small number of people need to self-catheterize temporarily
• Percutaneous tibial nerve stimulation (PTNS): weekly 30-minute sessions of nerve stimulation near the ankle, then maintenance
• Implantable tibial nerve stimulators
• Sacral neuromodulation: an implanted device that modulates bladder nerve signals
• Surgery, such as bladder augmentation, rarely, for severe refractory cases

Living with OAB

Absorbent products, planning access to toilets and protecting the skin from moisture help daily life. OAB can affect sleep, mood, work, sex and confidence, and falls at night are a risk in older adults, so treating it matters. Many people improve substantially with a combination of measures.

Frequently asked questions

What are the symptoms of overactive bladder?

The main symptom is a sudden, strong urge to urinate that is hard to delay. Most people also urinate frequently, often 8 or more times a day, and wake at night to urinate. Some leak urine before reaching the toilet.

What causes overactive bladder?

Often there is no single cause. It is linked to aging, nerve conditions such as stroke or multiple sclerosis, prostate enlargement, menopause, obesity, diabetes, constipation, and drinks such as coffee and alcohol. A urine test rules out infection.

What is the best treatment for overactive bladder?

Many people improve with bladder training, pelvic floor exercises and cutting back on caffeine and alcohol. Medicines such as mirabegron or vibegron help if needed. Botox injections and nerve stimulation work for people who do not respond to other treatments.

Is overactive bladder a normal part of aging?

No. OAB becomes more common with age but is not normal or inevitable, and it is treatable at any age. Older adults should discuss treatment options, because some older bladder medicines can affect memory.

What is the difference between overactive bladder and stress incontinence?

Overactive bladder causes urgency and leakage with a sudden urge. Stress incontinence causes leakage with coughing, sneezing, laughing or exercise because of a weak pelvic floor or urethral support. Many people have both, called mixed incontinence.