Can I take Fluanxol and Prozac together?

Why this happens

Prozac (fluoxetine) blocks the liver enzymes (specifically CYP2D6) that your body uses to break down Fluanxol (flupentixol). This causes the levels of Fluanxol in your blood to rise significantly. Additionally, both drugs have a side effect that can affect the electrical activity of your heart.

What you should do

You must speak to your doctor before taking these together. They may need to lower your dose of Fluanxol or perform an ECG (heart trace) to check your heart rhythm. Seek immediate medical help if you feel dizzy, faint, or notice a fast or pounding heartbeat.

Important precautions

Increased Suicidal Thoughts

In the first few weeks of treatment, Prozac can increase thoughts of self-harm or suicide, particularly in patients under 25. You must be closely monitored by family or a doctor during this time.

Serotonin Syndrome

Taking these medicines together increases the risk of a life-threatening condition called serotonin syndrome. Seek urgent medical help if you experience high fever, agitation, confusion, or severe muscle twitching.

Parkinson's disease

Fluanxol can significantly worsen the symptoms of Parkinson's disease and should generally be avoided.

Heart rhythm disorders (Long QT syndrome)

Fluanxol can affect your heart rhythm. You must tell your doctor if you have a history of heart rhythm problems or are taking other medicines that affect the heart.

Bipolar disorder

Prozac can trigger a manic episode (periods of high energy, racing thoughts, and impulsive behaviour) if you have undiagnosed bipolar disorder.

Low sodium levels (hyponatremia)

Prozac can cause a serious drop in blood sodium levels, especially in older adults or those taking diuretics. Seek medical help if you experience severe confusion, weakness, or seizures.

Food and drink warnings

Alcohol

It is best to avoid or strictly limit alcohol when taking these medicines. Alcohol can significantly increase the sedative effects of Fluanxol and Prozac, making you feel very drowsy, dizzy, or uncoordinated. Combining alcohol with these medications also increases the risk of experiencing more severe side effects.

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.

Prozac can sometimes increase the effects of caffeine in your body. This may lead to feeling jittery, anxious, or having difficulty sleeping. If you notice these effects, you should limit your intake of caffeinated drinks.

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.