The Who, What, Where, When and Sometimes, Why.

St. John’s wort

St. John's wort

What is it?

St. John’s wort is a plant with yellow, star-shaped flowers and five petals that grows in Europe, North and South America, Australia, New Zealand, and Eastern Asia. The plant grows in sunny, well-drained areas. It grows to be 50-100 cm tall.

St. John’s wort might cause serious interactions with some drugs. Because of this, France has banned the use of St. John’s wort in products. Several other countries, including Japan, the United Kingdom, and Canada are in the process of updating warning labels on St. John’s wort products.

St. John’s wort is most commonly used for depression and conditions that sometimes go along with depression such as anxiety, tiredness, loss of appetite and trouble sleeping. There is some strong scientific evidence that it is effective for mild to moderate depression.

Other uses include heart palpitations, moodiness and other symptoms of menopause, mental disorders that present physical symptoms, premenstrual syndrome (PMS), attention deficit-hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), social phobia, and seasonal affective disorder (SAD).

St. John’s wort has been tried to help quit smoking, for fibromyalgia, chronic fatigue syndrome (CFS), burning feelings in the mouth, migraine and other types of headaches, muscle pain, nerve pain and nerve damage throughout the body, pain that travels down the sciatic nerve in the leg, and irritable bowel syndrome. It is also used for cancer (including brain cancer), HIV/AIDS, hepatitis C, herpes simplex, to help with a procedure to unblock clogged arteries, weight loss, and to treat a disease that causes the skin to lose color.

An oil can be made from St. John’s wort. Some people take this oil by mouth for indigestion. Some people apply this oil to their skin to treat bruises and scrapes, inflammation and muscle pain, scaly and itchy skin (psoriasis), first degree burns, wounds, tooth pulling, bug bites, hemorrhoids, nerve pain, and to treat a disease that causes the skin to lose color. But applying St. John’s wort directly to the skin is risky. It can cause serious sensitivity to sunlight.

In manufacturing, St. John’s wort extracts are also used in alcoholic beverages.

The active ingredients in St. John’s wort can be deactivated by light. That’s why you will find many products packaged in amber containers. The amber helps, but it doesn’t offer total protection against the adverse effects of light.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for ST. JOHN’S WORT are as follows:

Likely Effective for…

  • Depression. Taking St. John’s wort extracts improves mood and decreases anxiety and insomnia related to depression. It seems to be about as effective in treating depression as many prescription drugs. In fact, clinical guidelines from the American College of Physicians-American Society of Internal Medicine suggest that St. John’s wort can be considered an option along with antidepressant medications for short-term treatment of mild depression. However, since St. John’s wort does not appear to be more effective or significantly better tolerated than antidepressant medications, and since St. John’s wort causes many drug interactions, the guidelines suggest it might not be an appropriate choice for many people, particularly those who take other medications. St. John’s wort might not be as effective for more severe cases of depression.

Possibly Effective for…

  • Menopausal symptoms. Some evidence suggests that some specific combinations of St. John’s wort plus black cohosh (Remifemin; Gynoplus, Jin-Yan Pharm) can help improve menopausal symptoms such as hot flashes. The effects of St. John’s wort alone on menopausal symptoms are inconsistent. Some, but not all, research suggests that St. John’s wort might reduce hot flashes. However, St. John’s wort does not seem to improve sleep, quality of life, or other menopausal symptoms when used alone.
  • The conversion of mental experiences or states into bodily symptoms (somatization disorder). Treatment with a specific St. John’s wort product (LI 160, Lichtwer Pharma) daily for 6 weeks seems to reduce symptoms of somatization disorder.
  • Wound healing. Applying an ointment containing St. John’s wort three times daily for 16 days seems to improve wound healing and reduce scar formation after a Cesarean section (C-section).

Possibly Ineffective for…

  • Burning mouth syndrome. Taking St. John’s wort three times daily for 12 weeks does not reduce pain from burning mouth syndrome.
  • Hepatitis C virus (HCV) infection. Taking St. John’s wort by mouth does not seem to be effective for treating adults with hepatitis C virus infection.
  • HIV/AIDS. Taking St. John’s work by mouth does not seem to be effective for treating HIV-infected adults.
  • Irritable bowel syndrome (IBS). Early research shows that taking a specific St. John’s wort extract (St. John’s Wort Extract Extra Strength, Enzymatic Therapy) twice daily is not effective for reducing symptoms of IBS.
  • Nerve damage outside the brain or spinal cord (polyneuropathy). Taking St. John’s wort by mouth does not seem to relieve pain in diabetic or non-diabetic people with polyneuropathy.
  • Social phobia. Taking St. John’s wort daily does not seem to improve social phobia or social anxiety.

Insufficient Evidence to Rate Effectiveness for…

  • A procedure to widen blocked arteries (angioplasty). Early research shows that taking St. John’s wort three times daily for 2 weeks after a procedure to widen blocked arteries improves outcomes of the procedure in people who are also taking blood thinning medications. It is thought that St. John’s wort might help the blood thinning medications work better in some people.
  • Anxiety. Some reports suggest that taking St. John’s wort alone or together with valerian improves anxiety disorder. Also, taking one capsule of a specific product that contains St. John’s wort and valerian root (Sedariston Concentrate, Aristo Pharma GmbH) daily for one week, followed by one or two capsules twice daily for another week, reduces anxiety more than the medication diazepam.
  • Attention deficit-hyperactivity disorder (ADHD). Some research suggests that taking St. John’s wort daily for 4 weeks might improve attention and activity in adolescents with ADHD. But other research shows that taking a St. John’s wort extract for 8 weeks does not improve ADHD symptoms in children ages 6-17 years.
  • Brain tumor (glioma). Early research shows that taking hypericin, a chemical in St. John’s wort, by mouth for up to 3 months might reduce tumor size and improve the survival rate in people with brain tumors.
  • Herpes. Early research suggests that using a specific combination of St. John’s wort and copper sulfate pentahydrate (Dynamiclear) might help reduce symptoms, including stinging, burning and pain, in people with cold sores or genital herpes.
  • Migraine headache. Early research suggests that taking a specific St. John’s wort product (Perforan, Godaru, Iran) three times daily improves the severity of migraine pain but does not reduce how often migraines occur.
  • Obsessive-compulsive disorder (OCD). There is conflicting evidence about the effectiveness of St. John’s wort for OCD. The reason for contradictory findings could be due to differences in study design, differences in the St. John’s wort products used, or other factors.
  • Skin redness and irritation (plaque psoriasis). Early research suggests that applying St. John’s wort liquid or ointment to the skin decreases the severity and the size of psoriasis patches.
  • An ovary disorder known as polycystic ovary syndrome (PCOS). Early research shows that a product containing St. John’s wort and other herbs increases the frequency of menstrual periods and quality of life in women with PCOS. The effect of St. John’s wort alone is unknown.
  • Premenstrual syndrome (PMS). There is conflicting evidence about the use of St. John’s wort for treating PMS. Some early research suggests that St. John’s wort might help reduce PMS symptoms, including sleeping problems, coordination, confusion, crying, headache, fatigue, food cravings and swelling, by even as much as 50% in some women. However, other research shows that taking St. John’s wort does not reduce anxiety or other PMS symptoms.
  • Seasonal affective disorder (SAD). Early studies suggest that St. John’s wort might help SAD. It appears to improve symptoms of anxiety, decreased sex drive, and sleep disturbances associated with SAD. It is useful alone or in combination with light therapy.
  • Smoking cessation. Early research suggests that taking a specific St. John’s wort extract (LI-160, Lichtwer Pharma US) once or twice daily starting one week before and continuing for 3 months after quitting smoking does not improve long-term quit rates.
  • Tooth pulling. Early research suggests that applying a homeopathic St. John’s wort preparation does not improve dental pain after a tooth is pulled or after dental surgery.
  • Stomach upset.
  • Bruises.
  • Skin conditions.
  • Nerve pain.
  • Sciatica.
  • Excitability.
  • Fibromyalgia.
  • Chronic fatigue syndrome (CFS).
  • Muscle pain.
  • Cancer.
  • Weight loss.
  • Other conditions.

More evidence is needed to rate St. John’s wort for these uses.

For a long time, investigators thought a chemical in St. John’s wort called hypericin was responsible for its effects against depression. More recent information suggests another chemical, hyperforin, as well as adhyperforin, and several other similar chemicals may play a larger role in depression. Hyperforin and adhyperforin act on chemical messengers in the nervous system that regulate mood.

St. John’s wort is LIKELY SAFE when taken by mouth for up to 12 weeks. Some evidence suggests it can be used safely for over one year. It can cause some side effects such as trouble sleeping, vivid dreams, restlessness, anxiety, irritability, stomach upset, fatigue, dry mouth, dizziness, headache, skin rash, diarrhea, and tingling. Take St. John’s wort in the morning or lower the dose if it seems to be causing sleep problems.

St. John’s wort is POSSIBLY UNSAFE when taken by mouth in large dose. When taken by mouth in large doses, it might cause severe reactions to sun exposure. Wear sun block outside, especially if you are light-skinned.

St. John’s wort interacts with many drugs (see the section below). Let your healthcare provider know if you want to take St. John’s wort. Your healthcare provider will want to review your medications to see if there could be any problems.

There isn’t enough reliable information available to know if St. John’s wort is safe when it is applied to the skin. St. John’s wort might cause severe reactions to sun exposure.

Special Precautions & Warnings:

Pregnancy and breast-feeding: St. John’s wort is POSSIBLY UNSAFE when taken by mouth during pregnancy. There is some evidence that it can cause birth defects in unborn rats. No one yet knows whether it has the same effect in unborn humans. Nursing infants of mothers who take St. John’s wort can experience colic, drowsiness, and listlessness. Until more is known, do not use St. John’s wort if you are pregnant or breast-feeding.

Children: St. John’s work is POSSIBLY SAFE when taken by mouth for up to 8 weeks in children 6-17 years-old.

Alzheimer’s disease: There is concern that St. John’s wort might contribute to dementia in people with Alzheimer’s disease.

Anesthesia: Use of anesthesia in people who have used St. John’s wort for 6 months may lead to serious heart complications during surgery. Stop using St. John’s wort at least 2 weeks before a scheduled surgery.

Attention deficit-hyperactivity disorder (ADHD): There is some concern that St. John’s wort might worsen symptoms of ADHD, especially in people taking the medication methylphenidate for ADHD. Until more is known, don’t use St. John’s wort if you are taking methylphenidate.

Bipolar disorder: People with bipolar disorder cycle between depression and mania, a state marked by excessive physical activity and impulsive behavior. St. John’s wort can bring on mania in these individuals and can also speed up the cycling between depression and mania.

Depression: In people with major depression, St. John’s wort might bring on mania, a state marked by excessive physical activity and impulsive behavior.

Infertility: There are some concerns that St. John’s wort might interfere with conceiving a child. If you are trying to conceive, don’t use St. John’s wort, especially if you have known fertility problems.

Schizophrenia: St. John’s wort might bring on psychosis in some people with schizophrenia.

Surgery: St. John’s wort might affect serotonin levels in the brain and as a result interfere with surgical procedures. Stop using St. John’s wort at least two weeks before a scheduled surgery.

Alprazolam (Xanax)

Interaction Rating = Major Do not take this combination.

Alprazolam (Xanax) is commonly used for anxiety. The body breaks down alprazolam (Xanax) to get rid of it. St. John’s wort can increase how fast the body gets rid of alprazolam (Xanax). Taking St. John’s wort along with alprazolam (Xanax) might decrease the effectiveness of alprazolam (Xanax).

Ambrisentan (Letairis)

Interaction Rating = Minor Be watchful with this combination.

Talk to your health provider.

The body breaks down ambrisentan (Letairis) to get rid of it. St. John’s wort might increase how quickly the body gets rid of ambrisentan (Letairis ). But this effect is probably not a big concern.

Aminolevulinic acid

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Aminolevulinic acid can make your skin sensitive to the sunlight. St. John’s wort might also increase your sensitivity to sunlight. Taking St. John’s wort along with aminolevulinic acid might increase the chances of sunburn, blistering or rashes on areas of skin exposed to sunlight. Be sure to wear sunblock and protective clothing when spending time in the sun.

 

Birth control pills (Contraceptive drugs)

Interaction Rating = Major Do not take this combination.

Some birth control pills contain estrogen. The body breaks down the estrogen in birth control pills to get rid of it. St. John’s wort might increase the breakdown of estrogen. Taking St. John’s wort along with birth control pills might decrease the effectiveness of birth control pills. If you take birth control pills along with St. John’s wort, use an additional form of birth control such as a condom. 

Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

Boceprevir (Victrelis)

Interaction Rating = Minor Be watchful with this combination.

Talk to your health provider.

St. John’s wort contains a chemical called hypericin. Taking St. John’s wort with boceprevir (Victrelis) might increase the amount of hypericin in the body. This might increase the effects or side effects of St. John’s wort. But the significance of this potential interaction is not known.

Bupropion (Wellbutrin)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Bupropion (Wellbutrin) is a drug used for depression and to help quit smoking. The body breaks down bupropion (Wellbutrin) to get rid of it. St. John’s wort can increase how quickly the body gets rid of some medications. St. John’s wort might decrease the effectiveness of bupropion (Wellbutrin) by increasing how quickly the body breaks down bupropion (Wellbutrin).

Clopidogrel (Plavix)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down clopidogrel (Plavix) to a chemical that decreases blood clotting in the body. Taking St. John’s wort along with clopidogrel (Plavix) might increase how well the body breaks down clopidogrel (Plavix) and decrease blood clotting too much.

Clozapine (Clozaril)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down clozapine (Clozaril) to get rid of it. St. John’s wort might increase how quickly the body breaks down clozapine (Clozaril). This might decrease how well clozapine (Clozaril) works.

Cyclosporine (Neoral, Sandimmune)

Interaction Rating = Major Do not take this combination.

The body breaks down cyclosporine (Neoral, Sandimmune) to get rid of it. St. John’s wort can increase how quickly the body breaks down cyclosporine (Neoral, Sandimmune) and decrease how well it works.

Dextromethorphan (Robitussin DM, and others)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

St. John’s wort can affect a brain chemical called serotonin. Dextromethorphan (Robitussin DM, others) can also affect serotonin. Taking St. John’s wort along with dextromethorphan (Robitussin DM, others) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety.

Digoxin (Lanoxin)

Interaction Rating = Major Do not take this combination.

Digoxin (Lanoxin) helps the heart beat more strongly. St. John’s wort might decrease how much digoxin (Lanoxin) the body absorbs. By decreasing how much digoxin (Lanoxin) the body absorbs, St. John’s wort might decrease the effects of digoxin (Lanoxin).

Docetaxel (Docefrez, Taxotere)

Interaction Rating = Major Do not take this combination.

St. John’s wort might increase how quickly the liver breaks down some medications. Taking St. John’s wort along with some medications that are changed by the liver might decrease the effectiveness of some medications, including the cancer drug docetaxel.

Fenfluramine (Pondimin)

Interaction Rating = Major Do not take this combination.

Fenfluramine (Pondimin) increases a chemical in the brain. This chemical is called serotonin. St. John’s wort also increases serotonin. Taking fenfluramine with St. John’s wort might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, nausea, headache, and anxiety.

Fentanyl (Duragesic)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Fentanyl (Duragesic) is used to treat pain. The body breaks down fentanyl to get rid of it. St. John’s wort might increase how quickly the body gets rid of fentanyl. Taking St. John’s wort along with fentanyl might decrease its effectiveness.

Fexofenadine (Allegra)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down fexofenadine (Allegra) to get rid of it. St. John’s wort might decrease how quickly the body gets rid of fexofenadine. This could cause fexofenadine (Allegra) to stay in the body too long. This could lead to increased effects and side effects of fexofenadine (Allegra).

Finasteride (Proscar, Propecia)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down finasteride (Proscar, Propecia) to get rid of it. St. John’s wort might increase how quickly the body gets rid of finasteride (Proscar, Propecia). Taking St. John’s wort along with finasteride (Proscar, Propecia) might decrease its effectiveness .

Gliclazide (Diamicron, others)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Gliclazide (Diamicron, others) is used to lower blood sugar levels in people with diabetes. The body breaks down gliclazide to get rid of it. St. John’s wort might increase how quickly the body gets rid of gliclazide. By increasing the breakdown of gliclazide St. John’s wort might decrease the effectiveness of gliclazide.

Imatinib (Gleevec)

Interaction Rating = Major Do not take this combination.

Imatinib is used to treat certain types of cancer. The body breaks down imatinib (Gleevec) to get rid of it. St. John’s wort might increase how quickly the body gets rid of imatinib (Gleevec). Taking St. John’s wort along with imatinib (Gleevec) might decrease the effectiveness of imatinib (Gleevec).

Irinotecan (Camptosar)

Interaction Rating = Major Do not take this combination.

Irinotecan (Camptosar) is used to treat cancer. The body breaks down irinotecan (Camptosar) to get rid of it. St. John’s wort might increase how fast the body breaks down irinotecan (Camptosar) and decrease the effectiveness of irinotecan (Camptosar).

Ivabradine (Corlanor)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Ivabradine (Corlanor) is used to treat heart problems. The body breaks down ivabradine (Corlanor) to get rid of it. St. John’s wort might increase how fast the body breaks down ivabradine (Corlanor) and decrease the effectiveness of ivabradine (Corlanor).

Ketamine (Ketalar)

Interaction Rating = Major Do not take this combination.

Ketamine (Ketalar) is a type of anesthetic used for pain control during surgery. The body breaks down ketamine (Ketalar) to get rid of it. St. John’s wort might increase how fast the body breaks down ketamine (Ketalar) and decrease the effectiveness of ketamine (Ketalar).

Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Some medications are changed and broken down by the liver. St. John’s wort might increase how quickly the liver breaks down some medications. Taking St. John’s wort along with some medications that are changed by the liver can decrease the effectiveness of some medications. Before taking St. John’s wort, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), zileuton (Zyflo), zolmitriptan (Zomig), and others.

Medications changed by the liver (Cytochrome P450 2B6 (CYP2B6) substrates)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Some medications are changed and broken down by the liver. St. John’s wort might increase how quickly the liver breaks down some medications. In theory, taking St. John’s wort along with some medications that are changed by the liver can decrease the effectiveness of some medications. Before taking St. John’s wort, talk to your healthcare provider if you take any medications that are changed by the liver.

Some of these medications that are changed by the liver include ketamine (Ketalar), phenobarbital, orphenadrine (Norflex), secobarbital (Seconal), and dexamethasone (Decadron).

Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Some medications are changed and broken down by the liver. St. John’s wort might increase how quickly the liver breaks down some medications. Taking St. John’s wort along with some medications that are broken down by the liver can decrease the effectiveness of your medication. Before taking St. John’s wort, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include amitriptyline (Elavil), carisoprodol (Soma), citalopram (Celexa), diazepam (Valium), lansoprazole (Prevacid), omeprazole (Prilosec), phenytoin (Dilantin), warfarin, and many others.

Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Some medications are changed and broken down by the liver. St. John’s wort might increase how quickly the liver breaks down some medications. Taking St. John’s wort along with some medications that are broken down by the liver can decrease the effectiveness of your medication. Before taking St. John’s wort, talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), warfarin (Coumadin), and others.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)

Interaction Rating = Major Do not take this combination.

Some medications are changed and broken down by the liver. St. John’s wort might increase how quickly the liver breaks down some medications. Taking St. John’s wort along with some medications that are broken down by the liver can decrease the effectiveness of some medications. Before taking St. John’s wort talk to your healthcare provider if you are taking any medications that are changed by the liver.

Some medications changed by the liver include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and many others.

Medications for depression (Antidepressant drugs)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

St. John’s wort increases a brain chemical called serotonin. Some medications for depression also increase the brain chemical serotonin. Taking St. John’s wort along with these medications for depression might increase serotonin too much and cause serious side effects including heart problems, shivering, and anxiety. Do not take St. John’s wort if you are taking medications for depression.

Some of these medications for depression include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa), amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and others.

Medications for depression (MAOIs)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

St. John’s wort increases a chemical in the brain. This chemical is called serotonin. Some medications used for depression also increase serotonin. Taking St. John’s wort with these medications used for depression might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, and anxiety.

Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

Medications for depression (Tricyclic antidepressants)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down medications for depression to get rid of them. St. John’s wort can increase how quickly the body gets rid of some of these medicines. St. John’s wort might decrease the effectiveness of some medications for depression by increasing how quickly the body breaks them down. 

Some of these medications for depression include amitriptyline (Elavil), clomipramine (Anafranil), nortriptyline (Pamelor), and others.

Medications for HIV/AIDS (Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs))

Interaction Rating = Major Do not take this combination.

The body breaks down medications used for HIV/AIDS to get rid of them. St. John’s wort can increase how quickly the body breaks down these medications. Taking St. John’s wort might decrease how well some medications used for HIV/AIDS work.

Some of these medications used for HIV/AIDS include etravirine (Intelence), nevirapine (Viramune), delavirdine (Rescriptor), and efavirenz (Sustiva).

Medications for HIV/AIDS (Protease Inhibitors)

Interaction Rating = Major Do not take this combination.

The body breaks down medications used for HIV/AIDS to get rid of them. Taking St. John’s wort might increase how quickly the body breaks down these medications. Taking St. John’s wort might decrease how well some medications used for HIV/AIDS work.

Some of these medications used for HIV/AIDS include amprenavir (Agenerase), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir), and saquinavir (Fortovase, Invirase).

Medications for migraine headaches (“Triptans”)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Some medications for migraine headaches can affect a chemical in the brain called serotonin. St. John’s wort can also affect serotonin. Taking St. John’s wort along with some medications for migraine headache might cause too much serotonin in the brain and serious side effects including confusion, shivering, stiff muscles, and other side effects.

Some medications for migraine headache include frovatriptan (Frova), naratriptan (Amerge), rizatriptan (Maxalt), sumatriptan (Imitrex), and zolmitriptan (Zomig).

Medications for schizophrenia (Atypical antipsychotics)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down some medications used for schizophrenia to get rid of them. St. John’s wort can increase how fast the body gets rid of these medications. Taking St. John’s wort along with medications for schizophrenia might decrease their effectiveness. 

Some of these medications used for schizophrenia are clozapine (Clozaril), olanzapine (Zyprexa), risperidone (Risperdal), quetiapine (Seroquel), and ziprasidone (Geodon).

Medications moved by pumps in cells (P-Glycoprotein Substrates)

Interaction Rating = Major Do not take this combination.

Some medications are moved by pumps in cells. St. John’s wort can make these pumps more active and decrease how much of some medications get absorbed by the body. This might decrease the effectiveness of some medications.

Some medications that are moved by these pumps include etoposide, paclitaxel, vinblastine, vincristine, vindesine, ketoconazole, itraconazole, amprenavir, indinavir, nelfinavir, saquinavir, cimetidine, ranitidine, diltiazem, verapamil, corticosteroids, erythromycin, cisapride (Propulsid), fexofenadine (Allegra), cyclosporine, loperamide (Imodium), quinidine, and others.

Medications that decrease cholesterol (“Statins”)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down some medications used to lower cholesterol to get rid of them. St. John’s wort can increase how fast the body gets rid of these medications. Taking St. John’s wort along with medications that lower cholesterol might decrease their effectiveness.

Some of these medications used for decreasing cholesterol include simvastatin (Zocor), atorvastatin (Lipitor), lovastatin, (Mevacor), and rosuvastatin (Crestor).

Medications that increase sensitivity to sunlight (Photosensitizing drugs)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Some medications can increase sensitivity to sunlight. St. John’s wort might also increase your sensitivity to sunlight. Taking St. John’s wort along with medications that increase sensitivity to sunlight could increase the chances of sunburn, blistering or rashes on areas of skin exposed to sunlight. Be sure to wear sunblock and protective clothing when spending time in the sun.

Some drugs that can increase sensitivity to sunlight include naproxen (Aleve), amiodarone (Cordarone), amitriptyline (Elavil), ciprofloxacin (Cipro), levofloxacin (Levaquin), moxifloxacin (Avelox), trimethoprim/sulfamethoxazole (Septra), tetracycline, methoxsalen (Oxsoralen), glipizide (Glucotrol), lamotrigine (Lamictal), and others.

Meperidine (Demerol)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Meperidine (Demerol) can increase the amount of a chemical in the brain called serotonin. St. John’s wort can also increase serotonin in the brain. Taking St. John’s wort along with meperidine (Demerol) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety.

Mephenytoin (Mesantoin)

Interaction Rating = Major Do not take this combination.

Mephenytoin (Mesantoin) is changed and broken down by the body. St. John’s wort increases how quickly this medication is broken down by the body. This might decrease the effectiveness of mephenytoin (Mesantoin).

Methadone (Dolophine)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Methadone (Dolophine) is a narcotic pain reliever. The body breaks down methadone (Dolophine) to get rid of it. St. John’s wort might increase how fast the body breaks down methadone (Dolophine) and decrease the effectiveness of methadone (Dolophine).

Methylphenidate (Concerta, others)

Interaction Rating = Minor Be watchful with this combination.

Talk to your health provider.

Methylphenidate (Concerta, others) is used to treat attention deficit-hyperactivity disorder. Taking St. John’s wort along with methylphenidate might decrease how well methylphenidate works.

Nefazodone (Serzone)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Nefazodone (Serzone) is used to treat low mood. It can increase a chemical in the brain called serotonin. St. John’s wort can also increase serotonin. Taking St. John’s wort with nefazodone (Serzone) might cause too much serotonin in the body. This could lead to serious side effects including heart problems, shivering, and restlessness.

Nifedipine (Adalat, Procardia)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Nifedipine is used to treat high blood pressure and chest pain. The body breaks down nifedipine (Adalat, Procardia) to get rid of it. St. John’s wort might increase how fast the body breaks down nifedipine (Adalat, Procardia) and decrease the effectiveness of nifedipine (Adalat, Procardia).

Omeprazole (Prilosec, Zegerid)

Interaction Rating = Major Do not take this combination.

Omeprazole (Prilosec, Zegerid) is a type of antacid. The body breaks down omeprazole (Prilosec, Zegerid) to get rid of it. St. John’s wort can increase how quickly the body breaks down omeprazole (Prilosec, Zegerid). This could decrease the effectiveness of omeprazole (Prilosec, Zegerid).

Oxycodone (Oxycontin)

Interaction Rating = Major Do not take this combination.

Oxycodone is a narcotic pain reliever. The body breaks down oxycodone (Oxycontin) to get rid of it. St. John’s wort might increase how fast the body breaks down oxycodone (Oxycontin) and decrease the effectiveness of oxycodone (Oxycontin).

Paroxetine (Paxil)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Paroxetine (Paxil) is used to treat low mood. Paroxetine (Paxil) increases a chemical in the brain called serotonin. St. John’s wort also increases serotonin. Taking paroxetine (Paxil) and St. John’s wort together might cause there to be too much serotonin. This could lead to serious side effects including heart problems, shivering, and weakness.

Pentazocine (Talwin)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

St. John’s wort increases a brain chemical called serotonin. Pentazocine (Talwin) also increases serotonin. Taking St. John’s wort along with pentazocine (Talwin) might increase serotonin too much. This could cause serious side effects including heart problems, shivering, and nervousness. Do not take St. John’s wort if you are taking pentazocine (Talwin).

Phenobarbital (Luminal)

Interaction Rating = Major Do not take this combination.

Phenobarbital (Luminal) is used to prevent seizures. The body breaks down phenobarbital (Luminal) to get rid of it. St. John’s wort might increase how quickly the body breaks down phenobarbital. This could decrease how well phenobarbital (Luminal) works and increase the risk of seizures.

Phenprocoumon (Marcoumar, others)

Interaction Rating = Major Do not take this combination.

Phenprocoumon (Marcoumar, others) is a type of blood thinning drug used outside of the U.S. The body breaks down phenprocoumon to get rid of it. St. John’s wort increases how quickly the body breaks down phenprocoumon . This decreases the effectiveness of phenprocoumon .

Phenytoin (Dilantin)

Interaction Rating = Major Do not take this combination.

Phenytoin (Dilantin) is used to prevent seizures. The body breaks down phenytoin (Dilantin) to get rid of it. St. John’s wort might increase how quickly the body breaks down phenytoin. This might decrease the effectiveness of phenytoin (Dilantin) and increase the possibility of seizures.

Procainamide

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Procainamide is used for irregular heart rhythms. St. John’s wort extract might increase how much procainamide the body absorbs. This could increase the effects and side effects of procainamide . But the significance of this potential interaction is not known.

Reserpine (Raudixin, others)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

St. John’s wort can decrease the effects of reserpine.

Sedative medications (Barbiturates)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Medications that cause sleepiness and drowsiness are called sedatives. St. John’s wort might decrease the effectiveness of sedative medications. It is not clear why this interaction occurs. Some of these medications that cause sleepiness include pentobarbital (Nembutal), phenobarbital (Luminal), secobarbital (Seconal), and others.

Sertraline (Zoloft)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Sertraline (Zoloft) is used to treat low mood. Sertraline (Zoloft) can increase a chemical in the brain called serotonin. St. John’s wort also increases serotonin. This can cause there to be too much serotonin in the brain. This could lead to serious side effects including heart problems, shivering, and irritability.

 

Tacrolimus (Prograf, Protopic)

Interaction Rating = Major Do not take this combination.

Tacrolimus (Prograf, Protopic) decreases immune system activity, which helps treat eczema. The body breaks down tacrolimus (Prograf, Protopic) to get rid of it. St. John’s wort can increase how quickly the body breaks down tacrolimus (Prograf, Protopic). This can cause tacrolimus (Prograf, Protopic) to be less effective.

Theophylline

Interaction Rating = Minor Be watchful with this combination.

Talk to your health provider.

Theophylline is used for asthma and other lung problems. The body breaks down theophylline to get rid of it. St. John’s wort might increase how quickly the body gets rid of theophylline . Taking St. John’s wort along with theophylline might decrease its effectiveness. But it is not clear if this interaction is a big concern.

Tramadol (Ultram)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Tramadol (Ultram) is used for pain. The body breaks down tramadol (Ultram) to get rid of it. St. John’s wort might increase how fast the body breaks down tramadol (Ultram) and decrease the effectiveness of tramadol (Ultram). Also, tramadol (Ultram) can affect a chemical in the brain called serotonin. St. John’s wort can also affect serotonin. Taking St. John’s wort along with tramadol (Ultram) might cause too much serotonin in the brain. This could lead to serious side effects such as confusion, shivering, and stiff muscles.

Verapamil (Calan, others)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

The body breaks down verapamil (Calan, others) to get rid of it. St. John’s wort might increase how fast the body breaks down verapamil and decrease the effectiveness of verapamil.

Voriconazole (Vfend)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Voriconazole (Vfend) is used for fungal infections. The body breaks down voriconazole (Vfend) to get rid of it. St. John’s wort might increase how quickly the body gets rid of voriconazole (Vfend). Taking St. John’s wort along with voriconazole (Vfend) might decrease its effectiveness.

Warfarin (Coumadin)

Interaction Rating = Major Do not take this combination.

Warfarin (Coumadin) is used to slow blood clotting. The body breaks down warfarin (Coumadin) to get rid of it. St. John’s wort might increase the breakdown and decrease the effectiveness of warfarin (Coumadin). Decreasing the effectiveness of warfarin (Coumadin) might increase the risk of clotting. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Zolpidem (Ambien)

Interaction Rating = Moderate Be cautious with this combination.

Talk to your health provider.

Zolpidem (Ambien) is used for trouble sleeping. The body breaks down zolpidem (Ambien) to get rid of it. St. John’s wort might increase how quickly the body breaks down zolpidem (Ambien). Taking St. John’s wort and taking zolpidem (Ambien) might decrease the effectiveness of zolpidem (Ambien). However, if is not clear if this potential interaction is a big concern.

Herbs and supplements that contain cardiac glycosides

Herbs and supplements that contain cardiac glycosides are used to help the heart beat more strongly. St. John’s wort might decrease how much cardiac glycoside the body absorbs. By decreasing how much the body absorbs, St. John’s wort might decrease the effects of these herbs.

Herbs and supplements with serotonergic properties

St. John’s wort might increase the levels of a chemical in the brain called serotonin. Some other herbs and supplements might also increase serotonin in the brain. Taking St. John’s wort along with these herbs and supplements might cause too much serotonin in the brain. Some other herbs and supplements that affect serotonin levels include 5-hydroxytryptophan (5-HTP), Hawaiian baby woodrose, L-tryptophan, and SAMe.

Iron

St. John’s wort might decrease the absorption of iron.

Red yeast

St. John’s wort might increase how quickly the liver breaks down some medications called statins. Red yeast contains chemicals similar to statin-like drugs. In theory, St. John’s wort might reduce blood levels of chemicals in red yeast.

Tryptophan

Taking St. John’s wort with tryptophan might cause levels of a certain brain chemical, called serotonin, to become too high. High levels of serotonin might cause adverse effects, including confusion, shivering, stiff muscles, and others.

There are no known interactions with foods.

ADULTS

BY MOUTH:

  • For mild to moderate depression:
    • In most studies, St. John’s wort extract was standardized to 0.3% hypericin content and used at doses of 300 mg three times daily.
    • Some studies have used St. John’s wort extract standardized to 0.2% hypericin at doses of 250 mg twice daily.
    • St. John’s wort extract standardized to 5% hyperforin has been used at doses of 300 mg three times daily.
  • For premenstrual syndrome (PMS): St. John’s wort extract standardized to 0.3% hypericin dosed at 300 mg once daily has been used.
  • For body symptoms associated with depression: 300 mg three times daily of the standardized hypericin extract has been used.
  • For somatization disorder: a specific extract (LI 160, Lichtwer Pharma) 600 mg/day has been used.

APPLIED TO THE SKIN:

  • For wound healing: An ointment containing a 5% St. John’s wort extract applied three times daily beginning 24 hours after a C-section and continued for 16 days has been used.

Amber, Amber Touch-and-Heal, Barbe de Saint-Jean, Chasse-diable, Demon Chaser, Fuga Daemonum, Goatweed, Hardhay, Herbe à la Brûlure, Herbe à Mille Trous, Herbe Aux Fées, Herbe Aux Mille Vertus, Herbe Aux Piqûres, Herbe de Saint Éloi, Herbe de la Saint-Jean, Herbe du Charpentier, Herbe Percée, Hierba de San Juan, Hypereikon, Hyperici Herba, Hypericum perforatum, Klamath Weed, Millepertuis, Millepertuis Perforé, Rosin Rose, Saynt Johannes Wort, SJW, Tipton Weed.


 

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For the latest comprehensive data on this and every other natural medicine, health professionals should consult the Professional Version of the Natural Medicines. It is fully referenced and updated daily.

© Copyright 1995-2019. Therapeutic Research Faculty, publishers of Natural Medicines, Prescriber’s Letter, and Pharmacist’s Letter. All rights reserved.

 

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