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Can I take Pregabalin and Quinine together?

Drug interaction guide

Taking pregabalin and quinine together can increase the risk of side effects that affect your brain and nervous system. You may feel more sleepy, dizzy, or confused than usual. There is also a small risk that both medications could affect your heart rhythm or increase the chance of having a seizure, especially if you are already prone to them.

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Why this happens

Both drugs can slow down the central nervous system (additive effect). Additionally, while they work in different ways, both medications can influence the electrical activity in the heart and brain. Quinine can occasionally interfere with how other drugs are processed in the body, though pregabalin is mostly cleared by the kidneys.

Use this combination with caution. If you feel excessively drowsy, dizzy, or notice a fluttering sensation in your chest (palpitations), contact your doctor. Avoid driving or operating machinery until you are certain the combination does not impair your alertness. It is best to avoid or strictly limit alcohol, as it will make the sleepiness much worse.

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Mental health disorders

Pregabalin can cause suicidal thoughts or an urge to self-harm. You must seek medical help immediately if your mood changes or you have thoughts of hurting yourself.

Severe respiratory depression

Pregabalin can cause serious breathing problems, especially if you already have lung disease or if you take it with other sedating medicines like opioids. Seek emergency help if you experience slow, shallow, or difficult breathing.

Pregnancy

Pregabalin use during the first three months of pregnancy may increase the risk of birth defects. Effective contraception must be used during treatment.

Drug dependence and withdrawal

Pregabalin carries a risk of dependence and addiction. Do not stop taking it suddenly, as this can cause severe withdrawal symptoms such as seizures or anxiety.

Heart rhythm disorders (Long QT syndrome)

Quinine can cause serious, potentially life-threatening heart rhythm problems. Do not take this if you have a history of 'Long QT syndrome' or an irregular heartbeat.

Tinnitus (ringing in the ears) or optic neuritis

Stop taking quinine immediately and seek medical advice if you experience any changes to your hearing (such as ringing) or any sudden changes to your vision.

Thrombocytopenia (low blood platelets)

Quinine can cause a dangerous drop in blood platelets. Seek urgent medical help if you notice unexplained bruising, nosebleeds, or purple spots on your skin.

Alcohol

It is best to avoid or strictly limit alcohol while taking pregabalin. Combining alcohol with this medicine can significantly increase side effects such as extreme sleepiness, dizziness, and blurred vision. It can also increase the risk of breathing problems.

Grapefruit juice

Avoid drinking grapefruit juice or eating grapefruit while taking quinine. Grapefruit contains compounds that can increase the level of quinine in your blood, which significantly raises the risk of serious side effects, including heart rhythm problems.

Tonic water

Tonic water contains small amounts of quinine. While the levels are low, consuming large amounts of tonic water alongside your medication could potentially increase the risk of side effects.

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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.

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Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 25 Jan 2026 | Originally published
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