Blood
Medicines for Polycythaemia
A condition where the blood becomes thicker due to too many red blood cells, raising the risk of clots — managed to reduce the red cell count and clot risk.
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 Polycythaemia?
Polycythaemia means having too many red blood cells, which makes the blood thicker and slower-flowing and raises the risk of blood clots. There are two broad types.
- How it is treated: Treatment aims to reduce the thickness of the blood and the risk of clots, and depends on the type.
- Self-care: Not smoking, staying well hydrated, keeping active, managing cardiovascular risk factors, and treating contributing conditions (such as sleep apnoea) all help.
- When to seek help: See a GP about persistent headaches, dizziness, itching after bathing, or a ruddy complexion, or if a blood test shows a high red cell count.
What it is
Polycythaemia means having too many red blood cells, which makes the blood thicker and slower-flowing and raises the risk of blood clots. There are two broad types. Polycythaemia vera is a condition of the bone marrow (a type of blood disorder) in which too many red cells — and sometimes other blood cells — are produced; it is linked to a specific gene change. Secondary polycythaemia is when the body makes extra red cells in response to something else, such as low oxygen levels from lung or heart conditions, smoking, sleep apnoea, or living at high altitude. Symptoms can include headaches, dizziness, blurred vision, itching (especially after a warm bath), redness of the skin, and tiredness; some people have no symptoms and it is found on a blood test. Identifying the type and cause is key.
How it is treated
Treatment aims to reduce the thickness of the blood and the risk of clots, and depends on the type. For polycythaemia vera, regularly removing blood (venesection) lowers the red cell count, low-dose aspirin is often used to reduce clot risk, and some people need medicines to control blood cell production, with monitoring by a haematologist. For secondary polycythaemia, treating the underlying cause — such as managing a lung condition, sleep apnoea, or stopping smoking — is central. Managing general cardiovascular risk factors, and being alert to the signs of a clot, are important in both. Care is guided by the type, with specialist input for polycythaemia vera.
For this condition, these medicines
Medicine classes used for Polycythaemia
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
Not smoking, staying well hydrated, keeping active, managing cardiovascular risk factors, and treating contributing conditions (such as sleep apnoea) all help. Taking prescribed treatment (such as aspirin) and attending monitoring reduce clot risk.
When to get help
When to see a doctor
See a GP about persistent headaches, dizziness, itching after bathing, or a ruddy complexion, or if a blood test shows a high red cell count. Call 999 for signs of a clot: stroke symptoms (FAST), sudden breathlessness or chest pain, or a painful swollen leg.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
Answers
Polycythaemia: frequently asked questions
Why is polycythaemia a concern?
Having too many red blood cells makes the blood thicker and raises the risk of blood clots, which can cause serious problems such as stroke, heart attack or DVT. Treatment reduces the red cell count and clot risk.
What is the difference between polycythaemia vera and secondary polycythaemia?
Polycythaemia vera is a bone marrow disorder that overproduces red cells, linked to a gene change. Secondary polycythaemia is the body making extra red cells in response to something else, such as low oxygen, smoking or sleep apnoea.
Sources
Where this is drawn from
- NHS — Polycythaemia
- British Society for Haematology guidance
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