The antimuscarinic agents darifenacin, flavoxate, oxybutinin, propiverine, solifenacin, tolterodine and trospium are used to treat urge incontinence because of their ability to reduce involuntary detrusor muscle contractions and increase bladder capacity.

(Mild to moderate stress incontinence in women may be treated with the SNRI duloxetine, which tightens the urethra).

Dosage regimen

* Darifenacin: initially 7.5mg once daily, increasing after two weeks to 15mg once daily if necessary.

* Flavoxate: 200mg three times daily.

* Oxybutynin: initially 2.5-5mg two to three times daily, increased if necessary to a maximum 5mg four times daily. Elderly patients should be started on 2.5-3mg twice daily, increased to 5mg twice daily according to response and tolerance.

* Propiverine: 15mg one to three times daily, increased if necessary to a maximum of 15mg four times daily.

* Solifenacin: 5mg daily, increased if necessary to 10mg once daily.

* Tolterodine: 2mg twice daily; reduce to 1mg twice daily if necessary to minimise side effects.

* Trospium: 20mg twice daily before food.

Patient’s knowledge of the medicines use

* Antimuscarinics reduce the contractions that cause urgency and increase capacity.

* Antimuscarinics should be used with caution in the elderly.

* Trospium needs to be taken an hour before food or on an empty stomach.

Is the medicine working?

* Does the patient still need to pass urine more than eight times during the day or more than once or twice at night? If so, refer back to the GP.

* Monitor frequency of micturition, volume voided and the number of urge incontinence episodes.

Side effects

* Dry mouth, gastrointestinal disturbances, dry eyes, blurred vision, palpitations and skin reactions.

Monitoring

* Treatment should be reviewed after three to six months.

* Oxybutynin requires referral if vision becomes cloudy. If side effects of oral oxybutynin are intolerable and the patient has benefited from the drug, transdermal patches may be tried.

* Liver enzymes need checking for those on long-term propiverine.

* Check any other drug therapy is not exacerbating incontinence (e.g. timing of any diuretic doses may need altering).

Lifestyle  

* Bladder re-training, which aims to enable the patient’s bladder to tolerate normal stretching as it fills, can be beneficial in urge incontinence.

* Make sure patients know about pads, pants and incontinence devices such as catheters, which may be beneficial either temporarily or longer-term.

* Reduce caffeine and fluid intake.

* Stop smoking. Nicotine is a bladder irritant and smoking may cause coughing, which can trigger the incontinence.

* Lose weight, as excess weight can put pressure on the bladder.

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