St. John's Wort

Joyce Yu

| Student Pharmacist | Spring 2023

Common Names

St. John’s Wort has a scientific name of hypericum perforatum. However, it is also commonly referred to as Klamath weed or goatweed.

Background

St. John’s Wort is a plant with yellow flowers that has been used in traditional European medicine as far back as the ancient Greeks. The name St. John's wort apparently refers to John the Baptist, as the plant blooms around the time of the feast of St. John the Baptist in late June.

Mechanism of Action

Common Uses

St. John’s Wort is promoted for depression, menopausal symptoms, attention-deficit hyperactivity disorder (ADHD), somatic symptom disorder (a condition in which a person feels extreme, exaggerated anxiety about physical symptoms), obsessive-compulsive disorder, and other conditions.

The extract from the St. John’s Wort plant acts as a serotonin reuptake inhibitor. Serotonin uptake is reduced at neuronal synapses, along with dopamine and norepinephrine. A common belief is that elevated levels of neurotransmitters are helpful when treating depression.

Typical Dosage

300-400mg, up to three times a day to be taken with meals.

Available Dosage Forms

The plant is compressed as a dry herb into capsules/tablets. The tablets are also characterized into the regular coating and extended-release versions.

Side Effects

Insomnia, anxiety, dry mouth, dizziness, gastrointestinal symptoms, fatigue, headache, or sexual dysfunction may present after taking St. John’s Wort.

Effectiveness

Several studies support the therapeutic benefit of St. John's wort in treating mild to moderate depression. In fact, some research has shown the supplement to be as effective as several prescription antidepressants. However, there’s not enough information to prove its effectiveness in the treatment of severe depression.

Safety Warnings

Patients may experience an increased sensitivity to sunlight, especially when taken in large doses.

Summary of One Article/Study

The National Center for Complementary and Integrative Health has released its findings regarding St. John’s Wort and its effects on treating depression. They have gathered lots of information regarding the short-term effects of St. John’s Wort on depression. It’s not consistently effective and experts advise to not use it to replace conventional care. However, not enough information is known about the long-term effects. What we do know about the safety of St. John’s wort is that it limits the effectiveness of many prescription medicines and combining it with antidepressants can lead to a lifethreatening amount of serotonin produced.

Interactions with other Medications

Buproprion (Wellbutrin SR), Alprazolam (Xanax), dextromethorphan, fexofenadine (allegra), Omeprazole (Prilosec), Warfarin (Jantoven), narcotics, ketamine, statins, antidepressants

Opinion

I would only advise taking this medication if the patient is able to adhere to all requirements due to how reactive the medication is. In addition, only patients with mild condition depression should be taking this medication as directed due to the severity of potential side effects and the lack of information presented for severe clinical depression. ~J.

Yu

References

Hypericum perforatum. Hypericum perforatum (Common St. John's-wort, Goatweed, Klamath Weed, St. Johns Wort) | North Carolina Extension Gardener Plant Toolbox. https://plants.ces.ncsu.edu/plants/hypericum-perforatum/. Accessed February 25, 2023.

MEDSAFE. Interactions with St. John's Wort (Hypericum perforatum) Preparations. https://www.medsafe.govt.nz/profs/puarticles/sjw.htm. Accessed February 25, 2023.

St. John's Wort and Depression: In depth. National Center for Complementary and Integrative Health. https://www.nccih.nih.gov/health/st-johns-wort-and-depressionin-depth. Accessed February 25, 2023.

Emma Ronk – Student Pharmacist Spring 2023