St. John’s Wort

Hypericum perforatum

Hypericum perforatum
St John’s wort (SJW) is a yellow flowering plant from which extracts are used to make teas, liquid extracts, and supplements. It has been used in Traditional Chinese Medicine for centuries.

Acts as an anti-depressant and reduces inflammation and pain

There are promising animal studies that demonstrate pain relief and the ability to work in tandem with opioids for pain relief. However, a 2017 review of the evidence concluded that clinical research in this field is still scarce, and the few studies available on chronic pain produced negative results. Prospective randomised controlled clinical trials performed at low doses are needed to validate its potential efficacy in humans.

A large-scale meta-analysis of SJW for depression in 2017 concluded that for patients with mild-to-moderate depression, St John’s wort has comparable efficacy and safety when compared to SSRIs (standard prescribed medication for depression). The studies were limited to 12 weeks duration at the most so evidence is unclear for longer term, and was lacking for more severe depression.

Taken at the recommended dose, St John’s wort has few adverse effects (for example nausea, rash). However, research has shown that SJW altered the pharmacokinetics of drugs such as digoxin, tacrolimus, indinavir, warfarin, alprazolam, simvastatin, or oral contraceptives. Hyperforin is one of the active ingredients in an SJW extract and is the main culprit for interactions with prescription medicines. A 2020 review of SJW drug interactions recommended a safety threshold of maximum 1-mg hyperforin per day is recommended.

Talk to your doctor if you are taking prescribed medications before you start SJW.

Contact your doctor immediately if you are reading this and taking St John’s wort and notice signs or symptoms indicating that your medicine is less effective than usual.

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