Elsevier

Urology

Volume 54, Issue 6, December 1999, Pages 960-963
Urology

Rapid Communications
Quercetin in men with category III chronic prostatitis: a preliminary prospective, double-blind, placebo-controlled trial

https://doi.org/10.1016/S0090-4295(99)00358-1Get rights and content

Abstract

Objectives. The National Institutes of Health (NIH) category III chronic prostatitis syndromes (nonbacterial chronic prostatitis and prostatodynia) are common disorders with few effective therapies. Bioflavonoids have recently been shown in an open-label study to improve the symptoms of these disorders in a significant proportion of men. The aim of this study was to confirm these findings in a prospective randomized, double-blind, placebo-controlled trial.

Methods. Thirty men with category IIIa and IIIb chronic pelvic pain syndrome were randomized in a double-blind fashion to receive either placebo or the bioflavonoid quercetin 500 mg twice daily for 1 month. The NIH chronic prostatitis symptom score was used to grade symptoms and the quality-of-life impact at the start and conclusion of the study. In a follow-up unblind, open-label study, 17 additional men received 1 month of a supplement containing quercetin, as well as bromelain and papain (Prosta-Q), which enhance bioflavonoid absorption.

Results. Two patients in the placebo group refused to complete the study because of worsening symptoms, leaving 13 placebo and 15 bioflavonoid patients for evaluation in the blind study. Both the quercetin and placebo groups were similar in age, symptom duration, and initial symptom score. Patients taking placebo had a mean improvement in NIH symptom score from 20.2 to 18.8 (not significant), while those taking the bioflavonoid had a mean improvement from 21.0 to 13.1 (P = 0.003). Twenty percent of patients taking placebo and 67% of patients taking the bioflavonoid had an improvement of symptoms of at least 25%. In the 17 patients who received Prosta-Q in the open-label study, 82% had at least a 25% improvement in symptom score.

Conclusions. Therapy with the bioflavonoid quercetin is well tolerated and provides significant symptomatic improvement in most men with chronic pelvic pain syndrome.

Section snippets

Material and methods

Patients with chronic pelvic pain syndrome (CPPS) for at least 6 months were evaluated by history, physical examination, and examination and culture of expressed prostatic secretions, urethral swab, and first voided and midstream urine. The postmassage urine was omitted because prostatic fluid was obtained from all patients. Thirty patients without positive bacterial cultures localizing to the prostatic fluid were enrolled in the study after giving written informed consent. This study was

Results

All 15 patients randomized to quercetin completed the study; 2 of 15 patients randomized to placebo did not because of worsening symptoms. The final symptom scores of these 2 patients were not included in the analysis, but their lack of improvement was included. As seen in Table I, the groups did not differ significantly in age, symptom duration, initial number of white blood cells in the prostatic fluid, or NIH symptom score.

At the completion of the study, the mean symptom score improved from

Comment

Patients with chronic prostatitis refractory to conventional therapies are a great challenge and frustration in urologic practice.2 For those who do not respond to antibiotic therapy but have negative prostatic fluid cultures, the etiology is unclear. A proportion of these patients probably have true persistent bacterial infections; indeed, a significant proportion of men with culture-negative CPPS have positive bacterial signal in their prostatic fluid by 16S ribosomal RNA molecular techniques.

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      The investigators found low- to very low-quality evidence that antibiotics, alpha-blockers, 5alpha-reductase inhibitors), anti-inflammatories, phytotherapy, traditional Chinese medications, and intraprostatic botulinum instillation may reduce prostatitis symptoms without a raised incidence of adverse events in the short-term, except for alpha-blockers, which may be correlated with a rise in mild adverse events [7,19]. Focusing on phytotherapeutics and medical devices, the most analysed products included in previous studies were calendula-curcuma suppositories [20], oral formulation of cranberry [21], quercetin [22], and pollen extract [18,23]. In clinical trials, these treatments showed some beneficial effects on clinical symptoms compared to placebo (NIH-CPSI score mean difference: −5.02; 95% confidence interval: −6.81 to −3.23), but the quality of evidence was low, due to unclear or high risk of bias in most domains in most studies, and imprecision (the confidence interval crosses the threshold for the minimal clinically important difference) [7].

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    D. A. Shoskes and J. Rajfer own stock in companies that will benefit from sales of the supplements reported in this study.

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