Can I take Fluanxol and Venlafaxine together?

Why this happens

Both medications can affect the electrical activity of the heart (prolonging the QT interval). Additionally, both drugs influence brain chemicals like serotonin and dopamine, which can lead to additive side effects on the nervous system.

What you should do

You must speak to your doctor before taking these together. They may want to perform a heart trace (ECG) or blood tests to ensure it is safe for you. Seek immediate medical help if you feel a racing heartbeat, severe dizziness, fainting, or experience muscle twitching and high fever.

Important precautions

Mental health and mood disorders

Venlafaxine can cause an increase in suicidal thoughts or self-harm, particularly when first starting treatment or changing doses. Monitor your mood closely and seek urgent medical help if you notice any distressing changes.

High blood pressure (Hypertension)

Venlafaxine can significantly increase your blood pressure. You must have your blood pressure checked before starting treatment and regularly while taking it. If you have uncontrolled high blood pressure, this medicine may not be suitable for you.

Parkinson's disease

Fluanxol can worsen the symptoms of Parkinson's disease and may interfere with the effectiveness of Parkinson's medications. It should generally be avoided if you have this condition.

Heart rhythm disorders (Long QT syndrome)

Both medicines can affect your heart rhythm, especially if taken together or with other heart medications. Seek immediate medical help if you experience palpitations, fainting, or a very fast heartbeat.

Bleeding disorders

venlafaxine increases your risk of serious bleeding, especially if you are also taking aspirin, ibuprofen, or blood-thinning medications like warfarin.

Abruptly stopping treatment

Never stop taking venlafaxine suddenly. Doing so can cause severe withdrawal symptoms (discontinuation syndrome). Your dose must be reduced very gradually under medical supervision.

Serotonin Syndrome

Taking these medicines together, or with other pro-serotonergic substances, can cause a life-threatening build-up of serotonin. Seek urgent medical help if you experience high fever, agitation, confusion, or severe muscle twitching.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol while taking these medicines. Both Fluanxol and Venlafaxine can cause drowsiness and dizziness; alcohol will significantly increase these effects, making you more likely to have an accident or fall. Combining alcohol with these medications also increases the risk of liver damage.

Caffeine (Coffee, Tea, Energy Drinks)

Caffeine can interfere with how Fluanxol works. High amounts of caffeine may reduce the effectiveness of the medicine or worsen symptoms of restlessness and anxiety. Try to keep your caffeine intake consistent and moderate.

Venlafaxine can increase your blood pressure and heart rate. High amounts of caffeine can worsen these effects, potentially leading to palpitations, jitteriness, or anxiety. Monitor your intake if you feel these symptoms.

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.