To conduct a systematic review and, where possible, quantitative meta-analysis
of the existing evidence regarding the therapeutic efficacy and safety of
the saw palmetto plant extract, Serenoa repens ,
in men with symptomatic benign prostatic hyperplasia (BPH).
Studies were identified through the search of MEDLINE (1966-1997), EMBASE,
Phytodok, the Cochrane Library, bibliographies of identified trials and review
articles, and contact with relevant authors and drug companies.
Randomized trials were included if participants had symptomatic BPH,
the intervention was a preparation of S repens alone
or in combination with other phytotherapeutic agents, a control group received
placebo or other pharmacological therapies for BPH, and the treatment duration
was at least 30 days.
Two investigators for each article (T.J.W., A.I., G.S., and R.M.) independently
extracted key data on design features, subject characteristics, therapy allocation,
and outcomes of the studies.
A total of 18 randomized controlled trials involving 2939 men met inclusion
criteria and were analyzed. Many studies did not report results in a method
that permitted meta-analysis. Treatment allocation concealment was adequate
in 9 studies; 16 were double-blinded. The mean study duration was 9 weeks
(range, 4-48 weeks). As compared with men receiving placebo, men treated with S repens had decreased urinary tract symptom scores (weighted
mean difference [WMD], −1.41 points [scale range, 0-19] [95% confidence
interval (CI), −2.52 to −0.30] [n=1 study]), nocturia (WMD, −0.76
times per evening [95% CI, −1.22 to −0.32] [n=10 studies]), and
improvement in self-rating of urinary tract symptoms; risk ratio for improvement
(1.72 [95% CI, 1.21-2.44] [n=6 studies]), and peak urine flow (WMD, 1.93 mL/s
[95% CI, 0.72-3.14] [n=8 studies]). Compared with men receiving finasteride,
men treated with S repens had similar improvements
in urinary tract symptom scores (WMD, 0.37 International Prostate Symptom
Score points [scale range, 0-35] [95% CI, −0.45 to 1.19] [n=2 studies])
and peak urine flow (WMD, −0.74 mL/s [95% CI, −1.66 to 0.18] [n=2
studies]). Adverse effects due to S repens were mild
and infrequent; erectile dysfunction was more frequent with finasteride (4.9%)
than with S repens (1.1%; P
<.001). Withdrawal rates in men assigned to placebo, S repens, or finasteride were 7%, 9%, and 11%, respectively.
The existing literature on S repens for treatment
of BPH is limited in terms of the short duration of studies and variability
in study design, use of phytotherapeutic preparations, and reports of outcomes.
However, the evidence suggests that S repens improves
urologic symptoms and flow measures. Compared with finasteride, S repens produces similar improvement in urinary tract symptoms and
urinary flow and was associated with fewer adverse treatment events. Further
research is needed using standardized preparations of
to determine its long-term effectiveness and ability to prevent
Wilt TJ, Ishani A, Stark G, MacDonald R, Lau J, Mulrow C. Saw Palmetto Extracts for Treatment of Benign Prostatic HyperplasiaA Systematic Review. JAMA. 1998;280(18):1604–1609. doi:10.1001/jama.280.18.1604
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