Side Effects of Saw Palmetto
Saw palmetto may increase bleeding risk, requiring discontinuation 2 weeks before surgery, and can potentially cause gastrointestinal disturbances, headache, and dizziness, though it is generally well-tolerated with minimal serious adverse effects. 1
Primary Side Effects
Bleeding Risk
- Saw palmetto may increase bleeding time, leading to increased risk of hematuria and operative bleeding 1
- The mechanism is not precisely known, but it has been found to inhibit cyclooxygenase in rodents 1
- Case reports document coagulopathy and hematuria associated with saw palmetto use 2
- Guidelines recommend holding saw palmetto for 2 weeks before surgery due to bleeding concerns 1
Gastrointestinal Effects
- Common side effects include:
- Nausea
- Vomiting
- Abdominal pain
- Constipation or diarrhea
- A rare but serious case of pancreatitis has been reported with saw palmetto use 3
Other Reported Side Effects
- Headache
- Dizziness
- Fatigue
- Decreased libido (though uncommon)
Safety Profile
The Saw Palmetto for Treatment of Enlarged Prostates (STEP) study, a randomized clinical trial over a 1-year period, found:
- No significant differences between saw palmetto and placebo in serious adverse events (5.4% vs. 9.7%) 4
- No significant differences in non-serious symptomatic adverse events (34.8% vs. 30.1%) 4
- Only small differences in laboratory parameters (total bilirubin, potassium, and glycosuria) 4
Special Considerations
Effect on PSA Testing
- Saw palmetto may affect prostate-specific antigen (PSA) levels, potentially complicating prostate cancer screening 1
- The Mayo Clinic Proceedings and NCCN guidelines note that saw palmetto contains phytoestrogenic compounds that can affect serum PSA levels 1
- This could lead to unreliable cancer detection in men undergoing PSA testing
Drug Interactions
- May interact with:
- Anticoagulants (warfarin, aspirin, clopidogrel)
- Antiplatelet medications
- NSAIDs
- These combinations could potentially increase bleeding risk
Clinical Implications
Perioperative Management
- Discontinue saw palmetto 2 weeks before any surgical procedure 1
- This recommendation is particularly important for procedures with high bleeding risk
- For lower-risk procedures, the decision may be more nuanced, but caution is still advised
Monitoring
- Monitor for signs of bleeding in patients taking saw palmetto with anticoagulants
- Be aware of potential PSA level alterations when interpreting prostate cancer screening results
Efficacy Considerations
Despite widespread use for benign prostatic hyperplasia (BPH) symptoms, efficacy remains questionable:
- A randomized trial found that increasing doses of saw palmetto extract did not reduce lower urinary tract symptoms more than placebo 5
- This lack of proven efficacy should be considered when weighing potential side effects against benefits
Common Pitfalls
- Failing to inquire about saw palmetto use during medication reconciliation
- Not recognizing potential bleeding complications in patients taking saw palmetto with anticoagulants
- Misinterpreting PSA levels in men taking saw palmetto
- Not advising patients to discontinue saw palmetto before surgical procedures
While saw palmetto is generally well-tolerated with minimal serious adverse effects, healthcare providers should be aware of its potential side effects, particularly the increased bleeding risk, and advise patients accordingly.