Oxybutynin or venlafaxine for hot flushes in women who cannot or choose not to use hormone replacement therapy: randomised trial and economic evaluation (the BLUSH trial)
A clinical trial is directly comparing two non-hormonal drugs—oxybutynin, a bladder medication, and venlafaxine, an antidepressant—to see which better controls hot flushes and night sweats in menopausal women who cannot or choose not to take hormone replacement therapy. This matters because hot flushes affect most menopausal women, often for years, and can be more severe in those on breast cancer treatment, sometimes reducing adherence to that therapy. HRT is the most effective option, but many women have medical contraindications or prefer not to use it. The alternatives available are less effective and carry side effects, yet no robust head-to-head trial has compared these two common non-hormonal treatments. If the trial shows one drug is clearly superior, it could give women and their doctors a straightforward, evidence-based choice for managing symptoms without HRT. For women on breast cancer therapy, better symptom control might indirectly improve their continuation of cancer treatment. The economic evaluation will also tell the NHS whether the better drug is worth the cost, helping to allocate resources efficiently. The results are intended to support informed decision-making, not to transform infrastructure or supply chains.
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RESEARCH QUESTION Is oxybutynin more effective and better value for money than venlafaxine at controlling vasomotor symptoms (VMS) in two groups of women: those who prefer not to use menopausal Hormone Replacement Treatment (HRT), and those with contraindications to HRT. BACKGROUND Most menopausal women experience VMS, including hot flushes and night sweats, lasting several years. VMS are more frequent and intense in women taking breast cancer treatment, which can reduce compliance. All alternatives are less effective than HRT and have side effects. METHODS Design: Multi-centre, randomised, open, parallel, superiority trial with internal pilot, and a parallel economic evaluation. To be adequately powered to detect clinically meaningful effects in both populations, we will conduct two randomised controlled trials in parallel under a single master protocol. Setting: Women will be identified in gynaecology clinics, by oncology and GP databases searches and via direct to patient marketing Target population: Women with menopausal VMS who are either unable to take, or prefer not to take, HRT Health technologies being assessed: Oxybutynin: Extended release, oral, starting dose 5mg, max 15mg Venlafaxine: Modified release, oral, starting dose 37.5mg, max 75mg Primary Outcome: The average Hot Flush (HF) score (frequency x severity) over one week, at week 12 Secondary Outcomes: All measured at baseline, week 12, and 6 and 12 months and additional stated timepoints: Average HF score (also in weeks 4 and 8) Frequency and severity, individually, of hot flushes/night sweats (also in weeks 4 and 8) Time to onset of symptom relief Individual domains and total score of MENQOL-I (also at week 4) Health related quality of life (EQ-5D-5L) and capability-wellbeing (ICECAP-A) Patient acceptability of treatment (5-point Likert scale, also at week 4) Patient-reported global improvement Urinary urgency, frequency and incontinence (ICIQ-OAB) Sleep quality (PSQI) Work productivity and absenteeism (WHO HPQ) Common known side effects of each drug Change or cessation of treatment, and for cancer population, continuation of endocrine therapy Sample size: Both trials have been powered to detect a 4-point mean difference in HF Score (SD=12) at 12 weeks, with 90% power, 5% 2-sided significance and 1:1 allocation. To allow for ~20% loss to follow-up and treatment discontinuation, 480 participants will be recruited per trial. Economic evaluation: From the perspectives of the NHS/social care, and of the wider society, cost-effectiveness will be evaluated using cost-consequence (including impact on individuals’ capability and productivity) and cost-utility (incremental costs per QALY) analyses. TIMELINES M1-M6: Protocol and database development, approvals, site set-up M7-M37: Clinic/ GP practice database searches and direct to patient adverts M10-M18 Pilot recruitment M19 Stop-go decision M19-M39 Continued recruitment M53 End of 1-year follow-up, data cleaned M54–M60 Data analysis, economic evaluation, reporting ANTICIPATED IMPACT AND DISSEMINATION The results will enable women to make informed decisions about treatments for VMS, and may indirectly improve adherence with breast cancer treatment. We will actively engage with all appropriate professional societies to appraise them of progress and outcome of the trial. Women’s Health Concern and Independent Cancer Patient Voices will lead on patient involvement.
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