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St John’s Wort (Supplement)

Last updated on 19/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions   |   Tips   |   Where To Buy  

GENERIC NAME: St John’s Wort / Hypericum perforatum

CHINESE NAME: 貫葉連翹

BRAND NAME(S) IN HONG KONG: California Gold, Gaia Herbs, Source Naturals, Solaray

DRUG CLASS: Herbal medicine

USED FOR: Short-term management of depression

OTHER DRUGS IN THE SAME CLASS: Chamomile, Coenzyme Q10, Cranberry, Echinacea, Ginkgo Biloba, Kava, Valerian

What is St John’s Wort for?

St. John’s Wort is a plant that grows in the wild. It is used as a treatment for depression especially in European countries. It might allow certain types of chemicals, namely serotonin, norepinephrine and dopamine, to stay longer in the brain in order to boost mood. However, there is limited scientific evidence to show that taking St. John’s Wort is effective in treating depression. Some studies suggest that St. John’s Wort may be effective in treating depressive symptoms in the short term. Ongoing studies are trying to understand if St. John’s Wort has anti-inflammatory and wound healing effects.

How to use it?

St. John’s Wort is taken by mouth in the form of tablets or capsules. The usual adult dose is 300-400 mg three times daily. For specific dosages, refer to the product label.

St. John’s Wort has several important drug interactions with medications such as Digoxin and Warfarin. Advise your doctor or pharmacist before taking any St. John’s Wort supplement.

What are the side effects of St John’s Wort ?

The side effects of taking St. John’s Wort are usually uncommon, but can include nausea and vomiting, diarrhoea, dizziness, tiredness, sensitivity to light, dry mouth, increased urination and swelling. Tremor, sweating, increased body temperature and fast heart beats might be resulted when St. John’s Wort is taken with selective serotonin reuptake inhibitors (SSRIs) such as Citalopram, Paroxetine and Sertraline.

Who should not take St John’s Wort?

– Pregnant or breastfeeding women
– Patients undergoing a surgical procedure

Pharmacist Tips:

The use of St John’s Wort for most conditions shows limited evidence of efficacy. Always consult your doctor or pharmacist before starting any supplement or herbal medicine. 

Common dosing schedule:
Take St John’s Wort as per product instructions. 

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications St John’s Wort may interact with:
Amlodipine
– Atazanavir
Carbamazepine
– Combined hormonal contraceptives
Digoxin
Warfarin
– Selective serotonin reuptake inhibitors, e.g. Escitalopram, Fluoxetine

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy St John’s Wort in Hong Kong?

In Hong Kong, St John’s Wort can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk/

Need more information?

For detailed information about the use of St John’s Wort in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.