Reviewed: Lopatkin N, Sivkov A, Walther C, Schlafke S, Medvedev A, Avdeichuk J, Golubev G, Melnik K, Elenberger N, Engelmann U. Long-term efficacy and safety of a combination of sabal and urtica extract for lower urinary tract symptoms: a placebo-controlled, double-blind, multicenter trial. World J Urol. June 1, 2005:139-146.

A new clinical trial supports the efficacy of an herbal combination in treating urinary tract difficulties in older men. The randomized, double-blind, placebo-controlled trial was conducted by researchers at the Institute of Urology in Moscow on 257 men age 50 or older with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH), a non-cancerous swelling of the prostate and the resulting urinary difficulties that affect many men over 50.

Each capsule of the herbal preparation combines 160 mg of WS® 1473, an extract of saw palmetto (Serenoa repens [W. Bartram] Small, Arecaceae) fruit, and 120 mg of WS® 1031, an extract of nettle (Urtica dioica L. ssp. dioica, Urticaceae) root. These extracts have each previously demonstrated beneficial effects on BPH. The combination of these extracts is called Prostagutt® forte (also known as PRO 160/120) and its safety and efficacy for treating symptoms associated with BPH have been documented in a recent publication.¹ (Prostagutt forte is manufactured under strict pharmaceutical standards by Willmar Schwabe Pharmaceuticals in Karlsruhe, Germany, and is imported into the United States and sold in health food stores as both ProstActive® Plus and ProstolTM by Nature’s Way of Springville, Utah.)

In the trial 257 subjects were randomized to receive either the herb combination (129 men) or placebo (128). A single-blind, 2-week, run-in placebo phase (i.e., the researchers knew that all men were receiving a placebo, but the men did not) was followed by a 24-week double-blind period in which the patients received 2 capsules per day of the herb combination or the placebo. This double-blind period was then followed by a 24-week open-control period during which all patients were administered PRO 160/120. The trial design also included an optional 48-week follow-up period after the control period, creating a total observation period of 96 weeks.

To determine the treatment efficacy of the herbal combination, researchers recorded patient assessment of LUTS by using the International Prostate Symptom Score (I-PSS) test, a self-rating questionnaire, as well as a quality of life index. Objective outcome measures included the maximum urinary flow rate, average urinary flow rate, urinary output, duration of urination and flow increase (all determined by means of an electronic uroflow recorder), residual urinary volume, and size of prostate (both determined by ultrasound).

Using the I-PSS, patients treated with PRO 160/120 exhibited a substantially higher total score reduction after 24 weeks of double-blind treatment than patients in the placebo group (6 points vs. 4 points; P=0.003). This corresponds to a reduction of 35.3 nd 23.5%, respectively. This improvement applied to men who experienced symptoms of urinary obstruction as well as to irritation and to patients who exhibited moderate or severe symptoms of BPH at the outset of the trial. Patients in the placebo group showed a marked improvement in LUTS (as measured by the I-PSS) after being switched to PRO 160/120 during the open control period (P=0.01, compared to those who had been treated with PRO 160/120 in the double-blind phase).

As with previous trials on saw palmetto and nettle root,¹ the outcomes show a high degree of safety for the herb combination. The incidence of adverse effects for the men in the herb group was the same as those in taking the placebo: 23 men (17.8% of 129) experienced adverse events in the PRO 160/120 group compared to 24 (18.8% of 128) in the placebo group, with the main adverse effects being respiratory system disorders. (Respiratory system disorders are not a common adverse effect of the use of saw palmetto or nettle root; since the incidence was about the same as in the placebo, this effect was probably a result of the general incidence in a normal population of men in this age group, i.e., over 50 years.) Thus, the tolerability of PRO 160/120 was judged comparable to the placebo.

Although the safety and efficacy of an herb or phytomedicinal product cannot be determined by the results of only one clinical trial, in the case of the saw palmetto and nettle root preparation, the combination of the literature on each ingredient, plus recent trials and the new trial on the combined formulation, demonstrate that this phytomedicine is both safe and effective for treating many symptoms of BPH. Further, in some trials the combined formulation has also been shown to be as effective for treating many of the parameters of BPH, with significantly less adverse effects, as standard drug therapy such as the widely used pharmaceutical finasteride (Proscar®).²

Meta-analyses of 18³ and 21⁴ randomized clinical trials have confirmed the safety and efficacy of saw palmetto preparations in treating symptoms of BPH. Both saw palmetto and nettle root are approved by the Commission E of the German Federal Institute for Drugs and Medical Devices (analogous to the US Food and Drug Administration) as nonprescription medications to treat symptoms of BPH.⁵

—Mark Blumenthal and Brenda Milot, ELS

References

1. Bondarenko B, Walther C, Funk P, Schlafke S, Engelmann U. Long-term efficacy and safety of PRO 160/120 (a combination of Sabal and Urtica extract) in patients with lower urinary tract symptoms (LUTS). Phytomedicine. 2003;10(Supp IV):53-55.

2. Sokeland J. Combined Sabal and Urtica extract compared with finasteride in men with benign prostatic hyperplasia: analysis of prostate volume and therapeutic outcome. BJU Int. September 2000;86(4):439-442.

3. Wilt TJ, Ishani A, Stark G, MacDonald R, Lau J, Mulrow C. Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA. 1998; 280(18):1604–1609.

4. Wilt T, Ishani A, MacDonald R. Serenoa repens for benign prostatic hyperplasia. The Cochrane Library 2004, Issue 2. Available at: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=DisplayFiltered&DB=pubmed Accessed August 17, 2005. 5. Blumenthal M, Busse WR, Goldberg A, Hall T, Riggins CW, Rister RS, eds. Klein S, Rister RS, trans. The Complete German Commission E Monographs—Therapeutic Guide to Herbal Medicines. Boston: Integrative Medicine Communications; 1998.