Can I take St John's wort and Sertraline together?

Do not take St John's wort if you are already taking sertraline.

If you are currently taking both, you should contact your GP or pharmacist immediately for advice before stopping either medication, as stopping antidepressants suddenly can also cause side effects.

Why this happens

Both sertraline and St John's wort work by increasing the levels of serotonin in the brain. When used at the same time, they have an 'additive effect', pushing serotonin levels far too high.

Additionally, St John's wort can change how the liver breaks down certain medicines, which can make the levels of sertraline in your blood unpredictable.

How to know if you're having a drug interaction

You may be experiencing an interaction between St John's wort and sertraline if:

• You feel agitated, restless, or unusually anxious.

• You experience confusion or changes in mental state.

• You notice tremors, muscle twitching, or shaking.

• You have excessive sweating, flushing, or fever.

• You develop a fast or irregular heartbeat.

• You experience diarrhoea or nausea.

• Symptoms start soon after starting, combining, or increasing the dose of either product.

What you should do

If you have any of the above symptoms, you should:

• Contact your GP or pharmacist immediately for advice.

• Seek urgent medical help if you develop high fever, confusion, severe agitation, or a fast heartbeat.

• Do not stop sertraline suddenly unless advised by a healthcare professional.

• Stop taking St John’s wort and inform your healthcare professional that you have been using it.

• Tell your healthcare professional about all other medicines and supplements you are taking.

Important precautions

Serotonin syndrome

Do not take St John's wort and sertraline together. Combining them can cause dangerously high levels of serotonin, leading to a life-threatening condition called serotonin syndrome. Symptoms include shivering, diarrhoea, confusion, and severe muscle stiffness.

Suicidal thoughts and self-harm

Antidepressants like sertraline and St John's wort can increase the risk of suicidal thoughts or self-harm, particularly in the first few weeks of treatment or when the dose is changed. Patients and carers should monitor for any changes in mood or behaviour and seek urgent medical help if these occur.

Increased bleeding risk

Sertraline can increase the risk of bleeding, especially if you are taking other medicines that affect blood clotting, such as aspirin, ibuprofen (NSAIDs), or warfarin. Seek medical advice if you notice unusual bruising or bleeding.

Drug Interactions

St John's wort makes many essential medicines less effective, including the contraceptive pill and blood thinners such as warfarin. This can lead to unplanned pregnancy or an increased risk of blood clots.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol while taking these medicines. Combining alcohol with sertraline or St John's Wort can increase drowsiness, dizziness, and impair your coordination. There is also a risk that alcohol may worsen your symptoms of depression or anxiety.

Grapefruit juice

Avoid drinking large amounts of grapefruit juice. Grapefruit contains compounds that can increase the levels of sertraline in your blood, which may increase the risk of side effects.

Caffeine (Coffee, Tea, Energy Drinks)

St John's Wort can sometimes increase sensitivity to caffeine, leading to feelings of restlessness, anxiety, or a racing heart. Monitor your intake if you feel jittery.

Foods high in tyramine

While the risk is lower than with older types of antidepressants, some people taking St John's wort may experience a rise in blood pressure if they consume very large amounts of foods high in tyramine (e.g., aged cheeses, cured meats, fermented products). Use these foods in moderation.

Using other medicines

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.