This information is about a drug called thalidomide. It is used to treat myeloma (a cancer of the plasma cell of the blood). Research is now looking to see whether it might be effective as a treatment for some other cancers. Thalidomide was originally developed to prevent morning sickness in pregnant women.

Many people have heard of thalidomide. Its use in treating sickness during pregnancy in the 1960s resulted in birth defects. The birth defects were caused because thalidomide changes the growth and development of new blood vessels. It affected the formation of blood vessels in the developing babies.

Generally, thalidomide is only available in specialist cancer treatment centres where research trials are taking place and specialist doctors have experience in its use.

It is available only to a small number of people in the UK. It is mainly given to particular patients if their specialist thinks it may help (this is called a named patient basis). It may also be given to people taking part in the research trials.

It is most commonly used to treat a type of cancer known as myeloma. Thalidomide may be given to help keep the myeloma in remission after treatment, or if the myeloma comes back after treatment.

How thalidomide works in the treatment of cancer is not fully understood. Cancers need to produce a network of new blood vessels in order to grow. Without forming these new blood vessels, cancers cannot grow larger than a pinhead. Researchers hope that thalidomide can stop cancers from developing new blood vessels. This should reduce the cancer’s supply of oxygen and nutrients, which, it is hoped, will cause the tumour to shrink, or at least to stop growing. Drugs that interfere with blood vessel growth in this way are called angiogenesis inhibitors or anti-angiogenics.

Thalidomide can also be helpful in reducing some of the unpleasant symptoms that people with cancer may have. A substance produced naturally in the body, called tumour necrosis factor (TNF), stimulates the immune system to attack any cells that may be harmful. When people have cancer, they may produce too much TNF. This causes their immune system to overreact and can lead to high temperatures, night sweats and severe weight loss. Thalidomide reduces the amount of TNF produced in the body and therefore may reduce these symptoms.

Thalidomide is available as white 25mg, 50mg or 100mg capsules or tablets.

Thalidomide tablets or capsules are swallowed whole with plenty of water an hour after food, preferably in the late evening. Thalidomide may be given in combination with chemotherapy drugs.

Each person's reaction to a cancer drug is different. Some people have very few side effects, while others may experience more. We have outlined the most common side effects. However, we have not included those that are very rare and therefore extremely unlikely to affect you. If you notice any effects that you think may be due to the drug but which are not listed here, please discuss them with your doctor or nurse.

Birth defects You must not become pregnant or father a child while taking thalidomide, as it causes severe abnormalities in developing babies. Women will be asked to have a pregnancy test, to check that they are not pregnant. They will also be advised to use a highly effective form of contraception (such as implanted, or injected contraception) as well as a barrier method (such as a condom or cap).

Men taking thalidomide are advised to use a condom during sexual intercourse even if they have had a vasectomy. Both men and women will be asked to use contraception for four weeks before starting treatment and for four weeks after treatment has finished.

Because of the potential birth defects that thalidomide can cause, it is likely that you will have to take part in a risk management programme. You will need to sign a consent form and may have to be registered with the company that makes the drug. Registration will usually involve answering a confidential telephone survey. Your hospital doctor can only prescribe four weeks of  thalidomide at a time, so you will need to make frequent visits to the hospital. Each time you have more thalidomide prescribed (every four weeks) you will need to register on the risk management programme and answer the safety questions.

Feeling sick (nausea) and being sick (vomiting) Most people have little or no nausea. You will probably be given anti-sickness (anti-emetic) medicines to take, but tell your doctor if the nausea becomes a problem.

Risk of blood clots Thalidomide may increase your risk of developing blood clots. These can be either a deep vein thrombosis (DVT), or a pulmonary embolism (PE), which is a clot in the lung. While taking thalidomide you may also be given warfarin (an anticoagulant) that will thin your blood and help to prevent any clots forming. Let your hospital doctor know if you develop any pain, swelling or redness in one of your calves (a possible DVT), or if you develop any breathlessness or chest pain (a possible PE).

Temporary reduction in the production of blood cells by the bone marrow This can result in anaemia, risk of bruising or bleeding and infection. Thalidomide has only a slight effect on bone marrow. However, it can often be given in combination with chemotherapy drugs. The extent to which your bone marrow is affected depends on which chemotherapy drugs, if any, are given in combination with the thalidomide. Your blood will be checked regularly to see how well your bone marrow is working.

If your temperature goes above 38°C (100.5°F), if you develop any unexplained bruising or bleeding, or you suddenly feel unwell, even if you have a normal temperature, contact your doctor or the hospital straight away.

Lethargy, sleepiness and loss of balance It is not unusual for people to feel sleepy when taking thalidomide. It is important to tell your doctor if you have these side effects. However, they may improve as you continue to take the drug. If you are sleepy, it is important not to drive or operate machinery. It may help to take the tablets in the evening.

Constipation This can usually be relieved by drinking plenty of fluids (2–3 litres a day), eating a high-fibre diet and taking gentle exercise. Sometimes you may need to take laxatives to stimulate your bowel. These can be prescribed by your doctor.

Loss of appetite A dietitian or specialist nurse at your hospital can give advice about loss of appetite.

Numbness or tingling in hands or feet This is due to the effect of thalidomide on the nerves and is known as peripheral neuropathy. You may also notice that you have difficulty in tasks like doing up buttons. Tell your doctor if you notice any of these side effects. They usually improve slowly a few months after the treatment ends.

Headache Let your doctor know if you have headaches while having treatment with thalidomide.

Dizziness on standing You may feel dizzy for a few moments if you stand up too suddenly. This is caused by a temporary fall in blood pressure. Move slowly from lying to sitting and then sitting to standing. Tell your doctor if you have ever had any blood pressure problems and about any medicines you are taking.

Rashes Thalidomide can cause a rash, which may be itchy. Your doctor can prescribe treatment to help reduce this.

Swelling and fluid retention You may find that your ankles swell, particularly if you have been standing still or sitting down for a time. Try to remember to keep your feet up if you are sitting still. Talk to your doctor about medicines that may help. If the swelling is uncomfortable, your doctor may be able to prescribe elastic stockings to keep it under control.

If you have any questions about these or any other side effects talk to your doctor or nurse. It is important to let them know if you have any symptoms or side effects that may be related to the treatment you are having.

• It is important to take your capsules at the right times. You must take them as directed by your doctor.
• Keep the capsules in a safe place where children cannot reach them, as thalidomide could harm them
• If your doctor decides to stop the treatment, return any remaining capsules to the pharmacist. Do not flush them down the toilet or throw them away
• If you forget to take a capsule do not take a double dose. Tell your doctor and keep to your regular dose schedule
• If you are sick just after taking the tablet, tell your doctor, as you may need to take another one
• Thalidomide may interact with alcohol. It is advisable not to drink alcohol while taking thalidomide
• Thalidomide may interact with other medicines that you are taking. Let your doctor know what medications you are taking, including herbal medicines and those you have bought over the counter.
• When planning overseas travel, check whether the country you are visiting has any special requirements regarding thalidomide. For example, Australia requires you to provide a letter from your doctor explaining why you are taking the drug.

This section has been compiled using information from a number of reliable sources including:

• Oxford Textbook of Oncology (2nd edition). Souhami et al. Oxford University Press, 2002.
• Martindale: The Complete Drug Reference (35th edition). Sweetman et al. Pharmaceutical Press, 2007.

For further references, please see the general bibliography.