Oxybutynin for detrusor instability with adjuvant salivary stimulant pastilles to improve compliance: results of a multicentre, randomized controlled trial D.G. TINCELLO*, E.J. ADAMS, J.R. SUTHERST and D.H. RICHMOND *University Department of Obstetrics & Gynaecology, and the Urogynaecology Department, Liverpool Women's Hospital, Liverpool, UK Objective To test the hypothesis that compliance with oxybutynin would be improved if the severity of dry mouth could be reduced, thus leading to improved urinary symptom response and improved outcome, in a randomized, controlled trial of oxybutynin with or without salivary stimulant pastilles in patients with detrusor instability. Patients and methods Sixty-seven women with detrusor instability were randomized to a variable dose regimen of oxybutynin with (37) or without (30) salivary stimulant pastilles for 8 weeks. Patients were asked to complete a baseline voiding diary. In weeks 1 and 2, patients were encouraged to adjust the dose of oxybutynin themselves to achieve optimum sympto- matic control. A second diary was completed in the sixth week and patients were reviewed at 8 weeks. The outcome measures were the compliance rate, follow- up attendance rate, maximum dose of medication, changes in voiding and incontinence episodes, and changes in severity of urgency and of dry mouth symptoms between the ®rst and sixth week. Results Of the 67 women, 32 (47%) completed the study; the proportion completing was the same in both groups. Four patients had stopped the medication and there was no difference in the distribution of maximum dosage achieved between the groups. Both groups reported a reduced severity of urgency symptoms and increased severity of dry mouth. There were no differences in reported symptom change between the groups during the study. Conclusions The combination of oxybutynin and salivary stimulant pastilles does not improve compliance or symptom relief compared with oxybutynin alone; it does not allow a greater dose of oxybutynin to be tolerated. Keywords Detrusor instability, drugs, treatment, rando- mized controlled trial Introduction Idiopathic detrusor instability is a common problem, accounting for 30±50% of cases of female urinary incontinence [1] and is characterized by uninhibited detrusor pressure increases in association with the symptom of urgency during ®lling cystometry [2]. Behavioural therapy, including bladder drill, acupunc- ture, psychotherapy, hypnotherapy and biofeedback, have been used with variable success, but the mainstay of treatment is drug therapy using agents with anti- cholinergic activity, e.g. oxybutynin, propantheline and imipramine. Oxybutynin chloride offers the most effective method of treating detrusor instability and is currently the most commonly prescribed drug. It is a tertiary amine compound which has antispasmodic, local anaesthetic and anticholinergic properties [3±5]. It appears to be safe and effective for long-term use, with up to a 70% subjective and 60% urodynamic improvement [6±9]. The anticholinergic side-effects of dry mouth (xerosto- mia), blurred vision and a `hang-over' type of headache are common [6,7,9], and up to 80% of women discontinue oxybutynin within 6 months [5,7,10]. Compliance has been improved by using staggered regimens, increasing the dose from an initially low level [11]. Various preparations for rectal and intrave- sical use have been developed, with reasonable success [12±14]. Arti®cial saliva or salivary stimulants have been used to alleviate xerostomia, with some success (J. Sutherst, personal communication). An informal comparison of Salivix 1 pastilles (Thames Laboratories, Consolidated Chemicals, Wrexham, UK) and other proprietary arti®cial saliva preparations showed that Salivix was ranked highest for acceptable taste and relief of xerostomia in a sample of 10 healthy volunteers (unpublished data). Salivix pastilles contain malic acid, the stimulatory Accepted for publication 22 November 1999 BJU International (2000), 85, 416±420 # 2000 BJU International 416