What is the maximum daily dose of St. John's wort (Hypericum perforatum)?

From the Guidelines

The maximum daily dose of St. John's wort (Hypericum perforatum) is typically 300-1800 mg of standardized extract, with dosages ranging from 300 mg/d to 1800 mg/d, as seen in clinical trials 1.

Key Considerations

• Most clinical studies use extracts standardized to contain 0.12% to 0.28% hypericin, with a common regimen being 300 mg taken three times daily.
• This dosage has shown effectiveness for mild to moderate depression in clinical trials, with similar response rates to second-generation antidepressants 1.
• St. John's wort can interact with many medications, including antidepressants, birth control pills, blood thinners, and some heart medications, by affecting liver enzymes that metabolize these drugs.
• Side effects may include dry mouth, dizziness, digestive upset, and increased sensitivity to sunlight.
• St. John's wort should not be combined with prescription antidepressants due to the risk of serotonin syndrome, a potentially dangerous condition.

Important Precautions

• Always consult with a healthcare provider before starting St. John's wort, especially if you're taking other medications or have existing health conditions.
• Patients treated with antidepressants had a significantly higher risk for treatment discontinuation and discontinuation due to adverse events compared to those on St. John's wort 1.

Clinical Evidence

• Meta-analyses of clinical trials have demonstrated no statistically significant difference in remission rates between patients treated with second-generation antidepressants or St. John's wort 1.
• The majority of trials took place in outpatient primary care clinics and enrolled more women than men, with most participants being female and between 30 and 50 years of age 1.

From the FDA Drug Label

Adults and adolescents (12 years and older) Take 10 drops three times daily or as recommended by your healthcare practitioner. The maximum daily dose of St. John's wort is 30 drops per day, as the recommended dose is 10 drops three times daily 2, 2.

• The dose limit for children under 12 years is not specified, and they should take it under the direction of their healthcare practitioner.
• It is essential to follow the healthcare practitioner's recommendation for the dose, as it may vary.

From the Research

Dose Limit for St. John's Wort

The maximum daily dose of St. John's wort (Hypericum perforatum) is not strictly established, but several studies provide guidance on typical dosages used in clinical trials.

• A study from 1998 3 mentions that a high-dose course of treatment with St. John's wort preparations is 900 mg daily.
• Another study from 2001 4 used St. John's wort extract at a dose of 900 mg/d for 4 weeks, which could be increased to 1200 mg/d if there was no adequate response.

Safety and Efficacy

It's important to note that while St. John's wort may be effective for mild and moderate depression, its efficacy for major depression is less clear 4, 5.

• The safety profile of St. John's wort appears to be favorable, with few adverse effects reported 3, 6.
• However, St. John's wort can interact with various drugs, which may lead to decreased efficacy or increased risk of adverse reactions 7.

Dosage Considerations

When considering the use of St. John's wort, it's crucial to be aware of potential interactions with other medications and to consult with a healthcare professional.

• The dosage of St. John's wort may need to be adjusted based on individual response and potential interactions with other drugs 7.
• More research is needed to fully understand the efficacy and safety of St. John's wort, particularly in severely depressed patients and in long-term use 5.