Exploring the Benefits, Risks, and Clinical Implications of Herbal Supplements

Herbal supplements have been used for centuries in traditional medicine, and are still used today.^1,2 These products are derived from plants and are used for various health benefits.³

Herbal supplements are easier to access than pharmaceuticals because they do not require a prescription and are generally inexpensive. Some individuals prefer the use of herbal supplements as a more natural and safer alternative to modern medicine and/or may prefer the ability to treat themselves instead of seeking care from a health system or a provider.²

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These products also generally include a disclaimer noting that the product is not approved by the FDA, and that the actual benefits of the product are inconclusive. Herbal supplements are not subject to the same regulations as prescription medications; under the Dietary Supplement Health and Education Act of 1994, the FDA categorizes these products as exempt from the approval process required for medications.^2,3 As a result, herbal supplements can be sold without proof of effectiveness as long as they do not claim to prevent, treat, or cure any disease.³ This means these products are readily available for purchase without any guarantee about their purity or potency as the FDA’s role is limited to post-market surveillance.²

Since the FDA does not have the resources to inspect every herbal supplement on the market, it prioritizes products that may cause injury or illness. After products reach the shelves, the FDA investigates any adverse effects (AE) reports and complaints from consumers and health care professionals. If the FDA determines a product presents safety risks to consumers, then it has the authority to enforce the law to pull the product from the shelves for consumer protection.⁴

Herbal supplements can vary widely in quality, with some products possibly containing unlisted ingredients, heavy metals, or contaminants that can pose risks to consumers.^1,2 These risks are why health care providers, especially pharmacists, should actively discuss herbal supplement use with patients to identify potential risks and interactions. Some of these risks include reducing prescription drug efficacy, inducing serotonin syndrome, and causing excessive sedation, which all affect patient safety.^2,3

St John’s Wort

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St John’s wort (SJW) is an herbal supplement with various uses for major depressive disorder, anxiety, menopausal symptoms, and wound healing.³ Its active compounds—hypericin and hyperforin—are thought to delay the reuptake of serotonin, norepinephrine, and dopamine, which can positively affect mood and reduce depressive symptoms.^5,6 Studies show SJW may offer similar efficacy to some selective serotonin reuptake inhibitor (SSRI) medications in depression. For example, Szegedi et al showed that SJW performed comparably to paroxetine (Paxil; Pexeva) in a controlled trial for moderate to severe depression.⁶ However, evidence supporting its use for severe depression is inconsistent, with some studies suggesting it may not provide significant benefit over placebo.⁵

While SJW is usually well-tolerated, it can cause AEs such as dizziness, dry mouth, gastrointestinal (GI) discomfort, and photosensitivity.^6,7 A significant concern with SJW is its potential for drug interactions due to its induction of the cytochrome P450 (CYP450) enzyme. The induction of the CYP450 enzyme can accelerate the metabolism of certain medications, which include anticoagulants, anticonvulsants, and oral contraceptives. This drug interaction can reduce drug efficacy, which increases the risk of treatment failure and poor outcomes.⁵ Additionally, combining SJW with medications that have similar mechanisms, like SSRIs, can lead to serotonin syndrome, a potentially life-threatening condition.^5,7

Pharmacists play an essential role in counseling patients on the safe use of SJW. This is especially true for individuals taking medications that inhibit the reuptake of serotonin or that are metabolized by CYP450. Monitoring for these drug interactions is key to preventing adverse patient outcomes.^5-7

Valerian

Valerian is an herbal supplement that has been used to manage menopausal symptoms, premenstrual syndrome, stress, and sleep disorders.³ The sedative effects of valerian make it a popular choice for people with insomnia. Although some studies report subjective improvements in sleep quality and sleep length, objective measures are inconsistent.⁸ For this reason, the American Academy of Sleep Medicine does not recommend valerian as a primary insomnia treatment.⁹

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Valerian is considered safe for short-term use. Mild AEs, such as dizziness, GI discomfort, and headache have been observed. At higher doses, valerian can cause drowsiness and impact heart rate.^8-10 Due to the possible risk of excessive sedation, it is important to avoid combining valerian with central nervous system (CNS) depressants, such as alcohol, benzodiazepines, and prescription sleep medications.^9,10

For patients interested in valerian, pharmacists play an important role in promoting its safe use. By monitoring patients for the use of any CNS depressants, pharmacists can help patients avoid concurrent use of valerian due to the risk of excessive sedation.^8-10

Saw Palmetto

Saw palmetto is an herbal supplement used to alleviate bothersome lower urinary tract symptoms (LUTS) and is especially used for LUTS associated with benign prostatic hyperplasia (BPH).³ It can also be used to increase sperm production and boost libido.

Several mechanisms for saw palmetto have been suggested. These include antiandrogenic, anti-inflammatory, and antiproliferative effects, but there is a lack of evidence for these mechanisms. A study by Barry et al found that saw palmetto did not significantly reduce LUTS more than placebo.¹¹

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Saw palmetto is generally well tolerated, with AEs that were not significantly different from placebo groups in clinical trials. Some people may experience GI discomfort, but severe AEs are unlikely to occur.^11,12 Despite its lack of AEs, the inconsistent efficacy of saw palmetto suggests it may not be a reliable option for managing BPH symptoms.^11,12

Pharmacists should inform patients who are considering saw palmetto about the lack of evidence regarding its effectiveness. In cases where patients seek symptom relief for BPH, discussing alternative options with more established efficacy may be appropriate.

The Role of Pharmacists

Pharmacists play a unique role in promoting patient safety when it comes to the use of herbal supplements. Many patients may assume that herbal supplements are safe because they are natural, so they may not disclose their use unless specifically asked. This is why it is important for pharmacists to ask not just about prescription and OTC medication use, but also about herbal supplements when performing a medication reconciliation. Additionally, a pharmacist’s role includes documenting herbal supplement use in patient records, collaborating with other health care providers, and reporting AEs. By proactively asking about and documenting herbal supplement use, pharmacists can identify potential risks and inform patients and their other providers about possible AEs to ensure appropriate use of herbal supplements and patient safety.

REFERENCES

1. Furhad S, Bokhari AA. Herbal supplements. In: StatPearls. StatPearls Publishing; 2024. Accessed November 13, 2024. https://www.ncbi.nlm.nih.gov/books/NBK536964/

2. Hassen G, Belete G, Carrera KG, et al. Clinical implications of herbal supplements in conventional medical practice: a US perspective. Cureus. 2022;14(7):e26893. doi: 10.7759/cureus.26893

3. Williams CT. Herbal supplements: precautions and safe use. Nurs Clin North Am. 2021;56(1):1-21. doi:10.1016/j.cnur.2020.10.001

4. Questions and answers on dietary supplements. FDA. February 21, 2024. Accessed November 5, 2024. fda.gov/food/information-consumers-using-dietary-supplements/questions-and-answers-dietary-supplements

5. Canenguez Benitez JS, Hernandez TE, Sundararajan R, et al. Advantages and disadvantages of using St. John's wort as a treatment for depression. Cureus. 2022;14(9):e29468. doi:10.7759/cureus.29468

6. Szegedi A, Kohnen R, Dienel A, Kieser M. Acute treatment of moderate to severe depression with hypericum extract WS 5570 (St John's wort): randomised controlled double blind non-inferiority trial versus paroxetine. BMJ. 2005;330(7490):503. doi:10.1136/bmj.38356.655266.82

7. Gelenberg A, Freeman M, Markowitz J. Practice guideline for the treatment of patients with major depressive disorder. Am J Psychiatry. 2010;167:50.

8. Coxeter PD, Schluter PJ, Eastwood HL, Nikles CJ, Glasziou PP. Valerian does not appear to reduce symptoms for patients with chronic insomnia in general practice using a series of randomized n-of-1 trials. Complement Ther Med. 2003;11(4):215-222. doi:10.1016/s0965-2299(03)00122-5

9. Sateia MJ, Buysse DJ, Krystal AD, Neubauer DN, Heald JL. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults: an american academy of sleep medicine clinical practice guideline. J Clin Sleep Med. 2017;13(2):307-349. doi:10.5664/jcsm.6470

10. Valente V, Machado D, Jorge S, Drake CL, Marques DR. Does valerian work for insomnia? An umbrella review of the evidence. Eur Neuropsychopharmacol. 2024;82:6-28. doi:10.1016/j.euroneuro.2024.01.008

11. Barry MJ, Meleth S, Lee JY, et al. Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial. JAMA. 2011;306(12):1344-1351. doi:10.1001/jama.2011.1364

12. Avins AL, Bent S, Staccone S, et al. A detailed safety assessment of a saw palmetto extract. Complement Ther Med. 2008;16(3):147-154. doi:10.1016/j.ctim.2007.10.005