Cardiovascular
Medicines for Long QT syndrome
A heart rhythm condition, often inherited, that can cause dangerous fast rhythms and fainting or, rarely, sudden collapse — manageable with precautions and treatment.
Education and reference only. This explains which medicines are used and why, in plain language — it deliberately contains no doses and is not a substitute for advice from your doctor or pharmacist. Always discuss your own treatment with a qualified clinician, and check the BNF and the product labelling for prescribing detail.
Quick answer
What is Long QT syndrome?
Long QT syndrome is a condition affecting the heart's electrical system, where the heart takes longer than normal to recharge between beats (seen as a long "QT interval" on an ECG). This can occasionally trigger a sudden, dangerous fast heart rhythm, which may cause fainting, seizures, or, rarely, cardiac arrest and sudden death — sometimes brought on by exercise, strong emotion, sudden noise, or during sleep.
- How it is treated: Management aims to reduce the risk of dangerous rhythms and is tailored to the individual and the cause.
- Self-care: Avoiding medicines that prolong the QT interval (carrying a list), correcting and avoiding salt imbalances, following individualised advice on exercise, taking prescribed treatment, and family screening all help reduce risk in long QT syndrome.
- When to seek help: See a doctor about fainting during exercise or emotion, a family history of long QT syndrome or unexplained sudden death in young relatives, for assessment.
What it is
Long QT syndrome is a condition affecting the heart's electrical system, where the heart takes longer than normal to recharge between beats (seen as a long "QT interval" on an ECG). This can occasionally trigger a sudden, dangerous fast heart rhythm, which may cause fainting, seizures, or, rarely, cardiac arrest and sudden death — sometimes brought on by exercise, strong emotion, sudden noise, or during sleep. It can be inherited (running in families and sometimes causing unexplained fainting or sudden death in young people), or acquired, most often caused by certain medicines or by imbalances in the body's salts. It may be found after a fainting episode, on a routine ECG, or when family members are screened. Recognising it is important because it is manageable and the risks can be greatly reduced.
How it is treated
Management aims to reduce the risk of dangerous rhythms and is tailored to the individual and the cause. For the inherited form, this often includes medicines (such as certain beta-blockers) that reduce the risk, avoiding triggers, and avoiding medicines that further prolong the QT interval (a list is provided). Some people at higher risk benefit from an implanted defibrillator (ICD) that can treat a dangerous rhythm. Correcting salt imbalances and stopping any responsible medicine treats the acquired form. Family members are usually offered screening, as it is inherited. Advice on exercise and activities is individualised. With appropriate treatment and precautions, most people with long QT syndrome can lead normal lives while greatly reducing their risk.
For this condition, these medicines
Medicine classes used for Long QT syndrome
Each links to a full, dose-free guide — what it is, how it works, who can and cannot use it, side effects, interactions and FAQs.
Beyond medication
Lifestyle and self-care
Avoiding medicines that prolong the QT interval (carrying a list), correcting and avoiding salt imbalances, following individualised advice on exercise, taking prescribed treatment, and family screening all help reduce risk in long QT syndrome.
When to get help
When to see a doctor
See a doctor about fainting during exercise or emotion, a family history of long QT syndrome or unexplained sudden death in young relatives, for assessment. Call 999 for collapse, a seizure, or fainting with a racing heart.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
Answers
Long QT syndrome: frequently asked questions
What is long QT syndrome?
It is a condition where the heart takes longer to recharge between beats, which can occasionally trigger a dangerous fast rhythm causing fainting or, rarely, collapse. It can be inherited or caused by certain medicines or salt imbalances.
Can long QT syndrome be managed?
Yes. With medicines (such as certain beta-blockers), avoiding triggers and QT-prolonging drugs, correcting salt imbalances, and sometimes an implanted defibrillator, the risks can be greatly reduced and most people lead normal lives.
Sources
Where this is drawn from
- NHS — Long QT syndrome
- British Heart Foundation guidance
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