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

Why this happens

St John's Wort is a 'liver enzyme inducer'. This means it speeds up the process by which your liver breaks down certain medicines. Because it makes your body process solifenacin much faster than usual, the levels of the medicine in your blood drop, preventing it from working properly.

What you should do

You should avoid taking St John's Wort while you are prescribed solifenacin. If you are already taking both, do not stop the herbal remedy suddenly; instead, speak to your doctor or pharmacist. They can advise you on how to stop the supplement safely and may need to monitor your bladder symptoms or adjust your medication.

Important precautions

Glaucoma

Do not take solifenacin if you have narrow-angle glaucoma, as it can increase the pressure in your eyes and worsen the condition.

Urinary retention

Do not take solifenacin if you have difficulty emptying your bladder (urinary retention), as it may make this problem worse.

Depression

If you are taking St John's wort for low mood, be aware that antidepressants can occasionally increase thoughts of self-harm or suicide, particularly when first starting treatment. Seek urgent medical help if your mood worsens.

Drug interactions

St John's wort significantly reduces the effectiveness of many essential medicines, including the contraceptive pill, blood thinners (like warfarin), and transplant medications. Do not start it without a pharmacist checking all your other medicines.

Serotonin syndrome

Taking St John's wort with other antidepressants or triptans for migraine can cause serotonin syndrome, a potentially life-threatening reaction involving high body temperature, agitation, and muscle rigidity.

Photosensitivity

St John's wort can make your skin significantly more sensitive to sunlight, leading to severe sunburn or skin reactions even with limited exposure.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol while taking solifenacin. Both alcohol and solifenacin can cause drowsiness and blurred vision; combining them increases the risk of these side effects and may impair your coordination.

It is best to avoid or strictly limit alcohol while taking St John's Wort. Combining the two can increase drowsiness and dizziness, and may worsen the side effects of the herbal remedy.

Grapefruit Juice

Grapefruit juice can increase the level of solifenacin in your blood, which may increase the risk of side effects such as dry mouth, constipation, and blurred vision. It is best to avoid drinking large amounts of grapefruit juice.

Caffeine (Coffee, Tea, Energy Drinks)

You should limit your intake of caffeine. Solifenacin is used to treat an overactive bladder, but caffeine is a natural diuretic and bladder irritant that can worsen symptoms like urgency and frequency, potentially making your medication less effective.

Foods high in Tyramine (e.g., aged cheeses, cured meats, soy sauce, marmite, overripe fruit)

While less common than with older prescription antidepressants, St John's Wort can potentially interact with tyramine-rich foods, leading to a sudden, dangerous increase in blood pressure (hypertensive crisis). You should consume 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.