st. john's wort (generic name)
- Auto Immune Conditions
- Bladder & Kidney Health
- Brain & Nervous System
- Care Transitions
- Dental Health
- Emotional Health
- Eye Health
- Falls Prevention
- Financial Planning
- General Safety
- Health Care Basics
- Healthy Living
- Hearing Loss
- Heart Health
- High Blood Pressure
- Life Transitions
- Lung Health
- Men's Health
- Nutrition & Weight Management
- Pain Management
- Preventive Health
- Sexual Health
- Stomach & Digestive Health
- Stress & Anxiety
- Women's Health
TraditionWARNING: DISCLAIMER: The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
Adults (over 18 years old)
Clinical trials have used a range of doses, including 0.17-2.7 milligrams of hypericin by mouth, and 900-1,800 milligrams of St. John's wort extract daily by mouth.
1.5% hyperforin (verum) has been applied to the skin for the treatment of atopic dermatitis.
Children (under 18 years old)
There is not enough scientific data to recommend St. John's wort in children.
SafetyDISCLAIMER: Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.
Infrequent allergic skin reactions, including rash and itching, are reported in human studies.
Side Effects and Warnings
In published studies, St. John's wort has generally been well tolerated at recommended doses for up to 1-3 months. The most common adverse effects include gastrointestinal upset, skin reactions, fatigue/sedation, restlessness or anxiety, sexual dysfunction (including impotence), dizziness, headache, and dry mouth. Several recent studies suggest that side effects occur in one to three percent of patients taking St. John's wort, and that the number of adverse events may be similar to placebo (and less than standard antidepressant drugs). Animal toxicity studies have found only non-specific symptoms such as weight loss. One small study reported elevated thyroid stimulating hormone (TSH) levels to be associated with taking St. John's wort.
It has been reported that St. John's wort may cause psychiatric symptoms such as suicidal and homicidal thoughts.
Delayed ejaculation has been reported in animal studies.
Pregnancy and Breastfeeding
Interactions with Drugs
St. John's wort interferes with the way the body processes many drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood in the short-term (causing increased effects or potentially serious adverse reactions) and/or decreased in the blood in the long-term (which can reduce the intended effects). Examples of medications that may be affected by St. John's wort in this manner include carbamazepine, cyclosporin, irinotecan, midazolam, nifedipine, simvastatin, theophylline, warfarin, or HIV drugs such as non-nucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs). The U.S. Food & Drug Administration (FDA) suggests that patients with HIV/AIDS on protease inhibitors or non-nucleoside reverse transcriptase inhibitors avoid taking St. John's wort.
Taking St. John's wort with antidepressants may lead to increased side effects, including serotonin syndrome and mania. Serotonin syndrome is a condition defined by muscle rigidity, fever, confusion, increased blood pressure and heart rate, and coma. Mania is defined by symptoms of elevated or irritable mood, rapid speech or thoughts, increased activity, and decreased need for sleep. Using St. John's wort with MAOIs may also increase the risk of severely increased blood pressure. Cautious is also advised when using St. John's wort with tricyclic antidepressants.
Reports exist of altered menstrual flow, bleeding, and unwanted pregnancies in women taking birth control pills and St. John's wort at the same time. Although cases of interaction are rare, caution is advised when taking St. John's wort and coumarin-type anticoagulants (blood thinners). In general, individuals should check the package insert and speak with a qualified healthcare professional including a pharmacist about possible interactions with St. John's wort.
St. John's wort may lead to increased risk of sun sensitivity when taken with other drugs such as antibiotics or birth control pills. A possible interaction with loperamide (Imodium®) has been reported; confusion and agitation occurred in one patient taking St. John's wort, loperamide, and the herb valerian (Valeriana officinalis). St. John's wort may interact with triptan-type headache medications. Examples include naratriptan (Amerge®), rizatriptan (Maxalt®), sumatriptan (Imitrex®), and zolmitriptan (Zomig®). In theory, St. John's wort may also interact with certain chemotherapy drugs such as anthracyclines. St. John's wort may increase the anti-inflammatory effects of COX2 inhibitor drugs like Vioxx® or NSAIDS like ibuprofen (Motrin®).
St John's wort may increase imatinib clearance. Thus, patients taking imatinib should avoid taking St John's wort. Concomitant use of enzyme inducers, including St John's wort, may necessitate an increase in the imatinib dose to maintain effectiveness.
In higher doses, St. John's wort has been shown to decrease the blood concentrations of omeprazole, tolbutamide, caffeine, dextromethorphan, fexofenadine, carbamazepine, and cimetidine, among other medications. No relevant interaction has been seen with alprazolam, caffeine, tolbutamide, and digoxin by treatment with a low-hyperforin St. John's wort extract.
Caution is also advised when taking benzodiazepine tranquilizers, opioids, P-glycoprotein regulated drugs, antibiotics, antivirals, anesthetics, antifungals, sedatives, or drugs used for anxiety, heart problems, or seizures. In general, individuals should check the package insert and speak with a qualified healthcare professional including a pharmacist about possible interactions with St. John's wort.
Interactions with Herbs and Dietary Supplements
St. John's wort may interfere with the way the body processes certain herbs and supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood in the short-term, causing increased effects or potentially serious adverse reactions, or decreased in the blood in the long-term, which can reduce the intended effects.
Taking St. John's wort with herbs or supplements with antidepressant activity may lead to increased side effects, including serotonin syndrome, mania, or severe increase in blood pressure. There is a particular risk of these interactions occurring with agents that possess possible monoamine oxidase inhibitory properties.
St. John's wort may lead to increased risk of sun sensitivity when taken with capsaicin or other photosensitizing products. St. John's wort may interact with herbs that also possess cardiac glycoside properties and decrease blood levels.
A possible interaction with the herb valerian (Valeriana officinalis) has been reported; confusion and agitation occurred in one patient taking St. John's wort, loperamide (Immodium®) and valerian. However, St. John's wort and valerian are often used together, with few reported of adverse events. In theory, due to the presence of tannins, St. John's wort may inhibit the absorption of iron.
Although cases of interaction are rare, caution is advised when taking St. John's wort and herbs and supplements that may have blood-thinning effects.
Caution is also advised when taking red yeast rice or any herb or supplements that is P-glycoprotein regulated. In general, individuals should speak with a qualified healthcare professional, including a pharmacist, about possible interactions with St. John's wort.
Use cautiously when combining St. John's wort with herbs or supplements that have the following proposed effects: antibacterial, antiviral, or sedative. Also, St. John's wort may have a possible interaction with herbs or supplements used for anxiety, heart problems, or seizures.