Effect of oxybutynin on the QTc interval in elderly patients with urinary incontinence

• Published in: British journal of clinical pharmacology Vol. 41; no. 1; pp. 73 - 75
• Main Authors: HUSSAIN, R. M., HARTIGAN-GO, K., THOMAS, S. H. L., FORD, G. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.01.1996; Blackwell Science
• Subjects: Aged; Aged, 80 and over; ageing; Biological and medical sciences; Drug toxicity and drugs side effects treatment; Electrocardiography - drug effects; Heart Rate - drug effects; Humans; Mandelic Acids - pharmacology; Mandelic Acids - therapeutic use; Medical sciences; Middle Aged; oxybutynin; Parasympatholytics - pharmacology; Pharmacology. Drug treatments; QT interval; Toxicity: cardiovascular system; Urinary Incontinence - drug therapy; Human; QT interval; Urinary system disease; Arrhythmia; Toxicity; Cardiovascular disease; Urinary tract disease; Urinary incontinence; Voiding dysfunction; Antispasmodic agent; Heart disease; Bladder disease; Elderly; Parasympatholytic
• ISSN: 0306-5251; 1365-2125
• DOI: 10.1111/j.1365-2125.1996.tb00161.x

Terodiline, an anticholinergic drug with calcium antagonist properties, is associated with QT prolongation and ventricular arrhythmias. It is not known if oxybutynin, a drug with a similar pharmacological profile, causes QT prolongation. ECGs were obtained before and at least 4 weeks after commencement of oxybutynin (mean daily dose 7.6, range 2.5–10 mg), in 21 elderly (mean age 75, range 58–88 years) patients treated for urinary incontinence. Heart rate, (mean±s.d.) 74±11 us 69±11 beats min‐1, ‒6 (‒13,2), before us during oxybutynin therapy, mean difference (95% confidence intervals); PR interval, 168±27 us 156±27 ms, ‒11 (‒26,3); QTc 454±27 us 447±31 ms1 2, ‒9 (‒23,5), and QTc dispersion, QTc max‐QTc min, 68±24 us 63±26 ms1 2 ‒1 (‒15,14) were all unaltered by oxybutynin therapy. The lack of an effect on resting heart rate suggests that oxybutynin has little anticholinergic action at cardiac M2 receptors at usually administered doses. Oxybutynin therapy is not associated with QTc interval prolongation and is unlikely to produce ventricular arrhythmias.