Saw palmetto: Clinical Use. Dosage

The most studied saw palmetto preparation is a commercial product known as Permixon (Pierre Fabre Medicament, Castres, France), which is a liposterolic extract consisting of 80% free (e.g. 94 g/100 g extract) and 7% esterified fatty acids, as well as small amounts of sterols (beta-sitosterol, campesterol, stigmasterol, cycloartenol), and a minimum percentage of polyprenic compounds, arabinose, glucose, galactose, uronic acid, and flavonoids.

BENIGN PROSTATIC HYPERTROPHY

Saw palmetto extracts are extremely popular in Europe where herbal preparations represent approximately one-third of total sales of all therapeutic agents sold for the treatment of BPH.

Substantial evidence suggests that saw palmetto is an effective treatment for stages 1 and 2 of BPH. A 2002 Cochrane review assessing the results from 21 randomised trials involving 3139 men concluded that saw palmetto improves urinary scores, symptoms and urinary flow measures compared with placebo, with effects on symptoms scores and peak urine flow similar to the pharmaceutical drug finasteride. Additionally, its use is associated with fewer adverse effects compared with finasteride and typically, symptomatic relief is reported more quickly.

In 2004, an updated meta-analysis of 14 randomised studies and three open-label studies was published. The analysis used data from 4280 patients derived from clinical studies that had used Permixon. Peak urinary flow rate and nocturia were the two common end-points. Active treatment was associated with a mean reduction in the International Prostate Symptom Score (IPSS) of 4.78 (0.41). A significant improvement in peak flow rate and reduction in nocturia was also reported.

Since then, a double-blind study of 1 year of continuous treatment with saw palmetto extract (160 mg twice daily) failed to produce significant differences compared with placebo for the American Urological Association Symptom Index, maximal urinary flow rate, prostate size, residual volume after voiding, quality of life, or serum PSA levels. A closer look at the study reveals that some subjects with moderate to severe BPH were also included in the sample, which may have contributed to the results observed; however, this is speculative.

Comparisons with alpha-adrenoreceptor antagonists

Although several comparative trials have been undertaken with finasteride, only a few have compared it with alpha-adrenoreceptor antagonist drugs, which are also commonly used in BPH. The most recent was a large, randomised, double-blind study involving 811 men with symptomatic BPH, who were recruited from 11 European countries, which showed that Permixon 320 mg/day produced similar results to tamsulosin 0.4 mg/day (Omnic). More specifically, both treatments reduced the IPSS by an average of 4.4 in 80% of subjects. Those patients with the most severe disease experienced the greatest improvement in IPSS total score, with mean changes greater in the Permixon group than in the tamsulosin group (-8.0 and -6.8, respectively). In regard to safety, both treatments were considered well tolerated; however, ejaculation disorders were significantly more frequent with tamsulosin (4.2%) than with Permixon (0.6%). Although these results are promising, this study has been criticised for not including a placebo group as a comparator.

In a short 3-week study, Grasso et al (1995) compared the effects of alfuzosin (7.5 mg/day) with saw palmetto (320 mg/day) in 53 BPH subjects under double-blind test conditions. Both treatments were found to be as effective in regard to improving irritative score; with maximum and mean urine flow, however, alfuzosin was shown to more rapidly reduce symptoms of obstruction. Considering most studies have shown that 4-8 weeks’ treatment with the herb is required to produce maximal effects, the effect seen at 3 weeks is encouraging.

An earlier study compared the effects of prazosin with saw palmetto in 45 patients with BPH over a 12-week period. This study found that although both treatments reduced symptoms, prazosin was slightly more effective.

Changes to prostate size

It is still open to speculation as to whether saw palmetto affects prostate size, because studies have produced contradictory results. One open study of 1 55 men tested the effectiveness and tolerability of Permixon (150 mg twice daily) over 2 years, and not only detected a significant improvement in the IPSS and QOL marker, but also a decrease in prostate size and significant improvement in sexual function after the first year of treatment.

A longer 5-year study using Permixon in 25 subjects with BPH showed that a total daily dose of 320 mg twice daily also significantly reduced disease symptoms and improved QOL, while reducing prostate size by an average of 30%. In 2003, results from two animal studies showed that saw palmetto (whole berry and extract) significantly diminished prostatic hyperplasia. In contrast, the 2005 study discussed earlier failed to find a significant effect on prostate size.

Commission E approves the use of saw palmetto for stages 1 and 2 of BPH.

Clinical note— Benign prostatic hypertrophy

BPH occurs in more than 50% of men over the age of 50 years. It is a slow, progressive enlargement of the fibromuscular and epithelial structures of the prostate gland, which can lead to obstruction of the ureter and urine retention. Symptoms such as frequent and/or painful urination, painful perineal stress, and a decrease in urine volume and flow can develop. The condition has four stages, with stage 1 considered mild, stages 2 and 3 considered more severe and often requiring pharmacological treatment, and stage 4 as severe and necessitating surgery.

ANDROGENETIC ALOPECIA

The idea of using saw palmetto for androgenetic alopecia (AGA) arose from the observation that finasteride appears to have some effect on this condition. One double-blind study has investigated the effects of saw palmetto as a potential therapeutic option, finding a highly positive response in 60% of subjects. A second double-blind study of 48 men and women with AGA noted that mean hair density increased by 17% after 10 weeks of treatment with a topical lotion containing saw palmetto and by 27% after 50 weeks of treatment compared to baseline.

CHRONIC PROSTATITIS AND PELVIC PAIN

Evidence to support the herb’s use in prostatitis is scarce. However, in April 2003 positive findings from a preliminary study using Permixon to treat symptoms of chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) were presented at the annual meeting of the American Urological Association (Anon 2003). The RCT involving 61 patients with category NIB CP/CPPS found that 75% receiving active treatment experienced at least mild improvement in symptoms, compared with 20% of the control group. Furthermore, 55% of patients receiving Permixon reported moderate or marked improvement, compared with 16% of the control group. In contrast, results from a 2004 prospective, randomised, open-label study failed to find benefits for saw palmetto (325 mg daily) in men diagnosed with category III CP/CPPS. After 1 year, the mean total National Institutes of Health Chronic Prostatitis Symptom Index score decreased from 24.7 to 24.6 (P= 0.41) and no benefits were seen for QOL or pain with saw palmetto treatment.

Saw palmetto:  Other Uses

Traditionally, saw palmetto has been used to treat a variety of urogenital conditions, such as impotence, male infertility and also as an aphrodisiac. It has also been used in female hirsutism, although its effectiveness in this condition is unknown.

Saw palmetto:  Dosage Range

• Liposterolic extract: 320 mg/day in divided doses.

• Dried berry: 2-4 g.

• Liquid extract (1:2): 2-4.5 mL/day.

ACCORDING TO CLINICAL STUDIES

• 160 mg twice daily of liposterolic extract taken long term.