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Clinical Trial Follow-up Evaluates Safety and Effectiveness of Saw Palmetto and Stinging Nettle in Men with Benign Prostatic Hyperplasia

Clinical Trial Follow-up Evaluates Safety and Effectiveness of Saw Palmetto and Stinging Nettle in Men with Benign Prostatic Hyperplasia

Article by Don Goldberg

Clinical Trial Follow-up Evaluates Safety and Effectiveness of Saw Palmetto and Stinging Nettle in Men with Benign Prostatic Hyperplasia

Lopatkin N, Sivkov A, Schlafke S, Fun P, Medvedev A, Engelmann U. Efficacy and safety of acombination of Sabal and Urtica extract in lower urinary tract symptoms - long-term follow-up ofa placebo-controlled, double-blind, multicenter trial. Int Urol Nephrol. February 15, 2007:DOI10.1007/s11255-006-9173-7.

Benign prostatic hyperplasia (BPH) is a noncancerous enlargement of the prostate gland, and it isthe leading cause of lower urinary tract symptoms common in older men. Lower urinary tractsymptoms include obstructive symptoms (decreased urine flow, interrupted flow, feelings ofincomplete emptying, and hesitancy) and irritative symptoms (urge to urinate, frequent urination,and nighttime urination). Although there are medications available to reduce BPH symptoms,many men find the side effects unacceptable. There is great interest in herbal remedies that arewell-tolerated and effective for continuous, long-term use. Extracts from saw palmetto (Serenoarepens; a.k.a. Sabal serrulata) and stinging nettle (Urtica dioica) are the most widely used herbalremedies for BPH. This article presents the results of a long-term follow-up of a clinical trialevaluating the safety and effectiveness of a combination of saw palmetto and stinging nettle inmen with BPH.

The study was conducted at three outpatient urology clinics in Moscow, Russia. The subjectswere men over the age of 50 years with a diagnosis of BPH. The herbal product studied was PRO160/120, which provided 160 mg ethanolic extract of saw palmetto fruit (WS(r) 1473) and 120mg ethanolic extract of stinging nettle root (WS(r) 1031) per capsule (Dr. Willmar SchwabeGmbH & Co., Karlsruhe, Germany; marketed as Prostagutt forte(r)). In the double-blind portionof the trial, 257 men were randomly assigned to receive 2 capsules per day of PRO 160/120 orplacebo for 24 weeks. In the open-label control portion of the study, all subjects took 2 capsulesper day of PRO 160/120 for 24 weeks. After the open-label portion of the study, subjects wereoffered an additional 48 weeks of open-label follow-up in which they continued to take 2capsules per day of PRO 160/120. The subjects returned for study visits every 12 weeks. Theinvestigators used ultrasound and electronic urinary flow meters to evaluate maximum urinaryflow rate, duration, output, residual urine volume, and prostate size. The subjects rated theirsymptoms using the International Prostate Symptom Score (I-PSS) questionnaire.

In the 24-week double-blind portion of the study, subjects taking PRO 160/120 reportedsignificant improvements in I-PSS scores compared to subjects taking the placebo (P < 0.02).Tolerability of PRO 160/120 was comparable to that of placebo. During the 24-week, open-labelcontrol period, the subjects who switched from placebo to PRO 160/120 had substantialimprovements in their I-PSS scores and subjects continuing on with PRO 160/120 had additionalmild improvements (P values not reported). By week 48, subjects in both groups reported amedian improvement of 7 points in I-PSS scores.

A total of 219 subjects continued in the follow-up study. From week 49 to week 96, I-PSS scoresimproved by a median of 1 point. Subjects reported 61 adverse events during the follow-upstudy; only one adverse event was assessed as being possibly related to PRO 160/120 treatment.

I-PSS scores improved significantly by 9 points from baseline to week 96, which corresponds toa 53% reduction from the baseline median of 17 points (P < 0.001). Similar improvements werereported for both the obstructive and irritative symptoms, and the improvement in each of theseven individual symptom scores was statistically significant (19%) (P < 0.01). Maximumurinary flow and average urinary flow values increased significantly (P < 0.01), residual urinevolume decreased significantly (44%) (P < 0.03), and prostate volume decreased significantly (P= 0.001) from baseline to week 96.

The authors conclude that PRO 160/120 slows the progression of BPH and provides a clinicallyrelevant benefit over a period of 96 weeks. Long-term administration of this combination of sawpalmetto and stinging nettle extracts showed very good tolerability and high acceptance by studyparticipants. The results from this study indicate that the combination product is slightly superiorto saw palmetto alone over a period of nearly two years. Although this study could be criticizedfor not continuing the randomized control group after the initial 24-week period, the independentethics committee that approved the study determined that it would be unethical for subjects to gowithout treatment for longer than 24 weeks. Placebo effects are common in studies investigatingmedical treatment of lower urinary tract symptoms, but the magnitude of the placebo effecttypically decreases over time. The continuous, long term improvements observed in this study donot appear to be explained by a placebo effect alone.

Herbclip. by Heather S. Oliff, PhD.

American Botanical Council, 6200 Manor Rd, Austin, TX 78723


The product used in this study is available in the United States under the name Prostolâ„¢, fromNature's Way.  The 60 softgel size is Willner code #39772 and the 120 softgel size is #39771.

According to Nature's Way, Prostolâ„¢ Dual Action Prostate Formula is the only prostate formulaproven to be a "dual enzyme inhibitor".*

Prostolâ„¢ combines the synergistic benefits of Sabal (saw palmetto) and Urtica (nettle) in apreparation proven to inhibit 5-reductase and aromatase activity.*