Deep Vein Thrombosis (DVT)

A deep vein thrombosis (DVT) is a blood clot which forms in a deep vein.  Blood clots that develop in a vein are also known as venous thrombosis.  DVT usually occurs in a deep leg vein, a larger vein that runs through the muscles of the calf and the thigh.


It can cause pain and swelling in the leg and may lead to complications such as pulmonary embolism. This is a serious condition that occurs when a piece of blood clot breaks off into the bloodstream and blocks one of the blood vessels in the lungs.


In some cases, there may be no symptoms of DVT. If symptoms do occur they can include:

  • Pain, swelling and tenderness in one of your legs (usually your calf).
  • A heavy ache in the affected area.
  • Warm skin in the area of the clot.
  • Red skin, particularly at the back of your leg below the knee.

DVT usually (although not always) affects one leg. The pain may be worse when you bend your foot upward towards your knee.  

Each year, DVT affects around 1 person in every 1,000 in the UK.  Anyone can develop DVT, but it becomes more common over the age of 40. As well as age, there are also a number of other risk factors, including:

  • Having a history of DVT or pulmonary embolism.
  • Having a family history of blood clots.
  • Being inactive for long periods – such as after an operation or during a long journey.
  • Blood vessel damage – a damaged blood vessel wall can result in the formation of a blood clot.
  • Having certain conditions or treatments that cause your blood to clot more easily than normal – such as cancer (including chemotherapy and radiotherapy treatment), heart and lung disease, thrombophilia and Hughes syndrome.
  • Being pregnant – your blood also clots more easily during pregnancy.
  • Being overweight or obese.

The combined contraceptive pill and hormone replacement therapy (HRT) both contain the female hormone oestrogen, which causes the blood to clot more easily. If you're taking either of these, your risk of developing DVT is slightly increased.


Our Advice

  • Try to avoid long periods of bed rest. If you have to stay in bed, keep your lower limbs moving on a regular basis.
  • Stop smoking.
  • Take regular exercise.
  • Use support stockings if you have varicose veins.
  • If you are taking a flight, use flight socks to improve circulation, walk around the plane whenever you can and drink plenty of water during the flight.
  • A low dose of aspirin also helps thin the blood but ask the pharmacist if you are taking any other medication or suffer from indigestion.
  • Our pharmacist can help you identify if you may be at higher risk from DVT.

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