Medicines

The most common treatment is anticoagulant (blood thinning) medicines, which reduce the blood's tendency to clot. These are usually taken for three to six months. Regular blood tests are needed to check the levels of the drug in the blood.

Anticoagulants can stop new blood clots from forming and old ones growing. They can't dissolve existing clots. The body does this itself over time.

The anticoagulants used are heparin (given through a vein as a "drip" or injected just under the skin twice each day) or warfarin (taken as tablets). Anyone taking these medicines should avoid activities that could increase the risk of injury. This is because one of the main ways a wound heals is through clotting, and anticoagulants interfere with this process.

Less commonly, clot dissolving drugs called thrombolytics are used to dissolve a DVT. They carry a high risk of bleeding, so are only used in severe cases, where a life or limb is threatened.

Compression stockings

To relieve pain and swelling, and to prevent post-thrombotic syndrome, some doctors recommend wearing graduated compression stockings (also called TED or thrombo-embolic deterrent stockings), which are tighter at the foot than higher up the leg. These may need to be worn for several months or more.

Putting your feet up

Most people with a DVT are advised to place a cushion under their feet while resting or sleeping, so that the feet are raised higher than the hips. This helps to reduce the pressure in the veins of the calves.

Preventing a DVT around surgery

Surgery and some medical treatments can increase the risk of having a DVT. So, hospitals often do a pre-operative risk assessment for DVT, which takes into account your personal risk factors and the type of surgery you are having. Various measures can then be used to keep the risk as low as possible. These include anticoagulant medicines, compression stockings, and an intermittent compression pump. This is a mechanical device that automatically squeezes the feet and lower legs. This helps the circulation of blood from the legs in the first few days after surgery.

General preventive advice

Anyone who feels they are at high risk of developing a DVT should seek medical advice. There are measures anybody can take to help prevent a DVT:

• exercise the legs regularly - take a brisk 30-minute walk every day
• maintain a weight that's appropriate for your height
• avoid sitting or lying in bed for long periods of time without moving the legs
• women, particularly those over the age of 35, should consider the risks and benefits of taking the contraceptive pill

Preventive measures for travelers

Although the added risk of developing a DVT caused by traveling appears to be low, it can be reduced even further by exercising the legs at least once every hour during long-distance travel. This means taking regular breaks if driving, or walking up and down the aisle of a coach, train or plane.

The muscles of the lower legs (which act as a pump for the blood in the veins) can be exercised while sitting by pulling the toes towards the knees then relaxing, or by pressing the balls of the feet down while raising the heel.

Other preventive measures

• don't take sleeping pills. These cause immobility, increasing the risk of DVT
• wear loose-fitting clothing
• keep the legs uncrossed
• keep hydrated by drinking normally (urine should be no darker than a pale yellow). Avoid alcohol to prevent dehydration
• wear graduated compression stockings. This is particularly important for travelers who have other risk factors for DVT

Some doctors recommend taking aspirin before traveling because of its blood thinning effects. But it is not suitable for children and can have side-effects. If in doubt, seek advice from a pharmacist or doctor.

People who have one or more of the risk factors mentioned earlier should seek medical advice before traveling.

Anyone who develops swelling or pain in the leg, or breathing problems after traveling should seek medical advice urgently.