Arsenic trioxide (Trisenox)
How does it work?
Trisenox infusion contains the active ingredient arsenic trioxide. It is used for the treatment of acute promyelocytic leukaemia (APL).
The bone marrow produces cells called stem cells. These normally develop into the different types of blood cells (white blood cells, red blood cells and platelets) and when these are mature they leave the bone marrow and enter the bloodstream.
In leukaemia the bone marrow produces too many immature white blood cells. These abnormal cells take up space in the bone marrow and result in less room for production of normal healthy blood cells. Acute promyelocytic leukaemia is a specific type of acute myeloid leukaemia in which the abnormal white blood cells cause problems with abnormal bleeding and bruising to occur.
It is not fully understood how arsenic trioxide works in treatment of promyelocytic leukaemia. However, it is known to damage cancer cells by causing the DNA structure to be changed and preventing the growth and multiplication of cancer cells.
Unfortunately, arsenic trioxide can also affect normal, healthy cells, particularly those that multiply quickly, such as blood cells and hair cells. The most important side effect is on the bone marrow where blood cells are made. Arsenic trioxide can temporarily decrease the production of healthy blood cells, leaving people susceptible to infection. Regular blood tests are therefore needed to monitor the levels of blood cells.
In most chemotherapy regimens, doses are administered in courses at various intervals to allow normal cells to recover from the adverse effects of the anticancer medicines between doses. However, during this period, cancer cells will also recover and start to replicate again. Successful treatment depends on the administration of the next course of therapy before the cancer cells reach their previous numbers and the net effect is to decrease the amount of cancer with each successive course.
What is it used for?
- Treatment of acute promyelocytic leukaemia (APL) in people who have already had other types of treatment, including a retinoid and chemotherapy, which have not worked well or no longer work.
How is this treatment given?
- Trisenox infusion is given via a drip into a vein (intravenously) over one to two hours by a doctor or nurse. It may be given over a longer period of time if you get side effects such as flushing or dizziness.
- The infusion is given daily until the leukaemia is in remission, for a maximum of 50 days. If no change in your condition is seen, then treatment will be discontinued. If this treatment is well tolerated and there has been an improvement in your condition, your doctor will start you on a consolidation treatment schedule (second treatment cycle) three to four weeks after the first course of treatment is completed.
- The second treatment cycle involves having an infusion every day for five days, followed by a two day break. This is repeated for a total of five weeks.
- This medicine can affect your heartbeat. For this reason your heart will need to be monitored with an ECG before treatment is started and regularly throughout your treatment. If you have any existing heart problems your heart may need to be continuously monitored with an ECG during your treatment.
- Tell your doctor straight away if you notice any of the following side effects while you are having treatment with this medicine: shortness of breath, coughing, chest pain, fever, sudden weight gain, water retention or swelling, fainting or palpitations (awareness of your heartbeat).
- During treatment with this medicine you will need to have regular blood tests to monitor your blood cells, your kidney and liver function and the levels of electrolytes (salts such as potassium and magnesium) and sugar in your blood.
- This medicine can affect the number of healthy blood cells in your blood. A low white blood cell count can increase your susceptibility to infections; a low red blood cell count causes anaemia and a low platelet count can cause problems with blood clotting. Tell your doctor immediately if you experience any of the following symptoms during your treatment, as they may indicate problems with your blood cells: unexplained bruising or bleeding, purple spots, black or tarry stools, sore mouth or throat, mouth ulcers, high temperature (fever) or other signs of infection, or suddenly feeling tired, breathless, or generally unwell.
- This medicine may be harmful to an unborn baby, and for this reason you should use effective contraception to avoid getting pregnant or fathering a child during treatment. You should continue to use contraception to prevent pregnancy for at least a few months after treatment with this medicine is stopped, but discuss this with your doctor. Women should consult their doctor immediately if they get pregnant during treatment.
- Your ability to get pregnant or father a child may be affected by this medicine. It is important to discuss fertility with your doctor before starting treatment.
- The safety and effectiveness of this medicine in children under five years old have not been studied.
Use with caution in
- Elderly people.
- Decreased liver function.
- Decreased kidney function.
- People with heart disease, such as heart failure, irregular heartbeats or a previous heart attack.
- People with a personal or family history of a type of abnormal heart beat seen on a heart monitoring trace (ECG) as a 'prolonged QT interval'.
- People taking other medicines that can increase the risk of a ‘prolonged QT interval’ (see end of factsheet for examples).
- People who have previously had treatment with anthracycline chemotherapy medicines such as doxorubicin (these can affect the heart).
- People with low levels of potassium or magnesium in their blood.
Not to be used in
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use in pregnancy has not been studied in humans. It should not be used in pregnancy, unless considered essential by your doctor due to life-threatening disease, because it is likely to be harmful to a developing baby.
- Women who could get pregnant should use effective contraception to prevent pregnancy, and men should use effective contraception to prevent fathering a child, both during treatment, and for at least a few months after treatment is finished. Seek further medical advice from your doctor.
- This medicine passes into breast milk and will be harmful to a nursing infant. Mothers who need treatment with this medicine should not breastfeed. Seek medical advice from your doctor.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Common (affect between 1 in 10 and 1 in 100 people)
- Increased blood sugar level (hyperglycaemia).
- Decreased level of potassium in the blood (hypokalaemia).
- Shortness of breath or painful breathing.
- Pins and needles sensations.
- Pain in the bones or joints.
- Elevated liver enzyme levels.
- Decrease in the number of healthy white blood cells or platelets in the blood (neutropenia or thrombocytopenia) – see warning section above.
- Abnormal heart rhythm, seen as a ‘prolonged QT interval’ on an ECG.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Chest pain.
- Increased heart rate (tachycardia).
- Heart disorders, such as leaking of fluid into the sac surrounding the heart (pericardial effusion) or heart failure.
- Build-up of fluid between the layers of tissue that line the lungs and chest cavity (pleural effusion).
- Increased level of white blood cells in the blood (leucocytosis).
- Increased levels of magnesium or sodium in the blood (hypermagnesaemia or hypernatraemia).
- Low levels of magnesium in blood (hypomagnesaemia).
- Low levels of oxygen in the tissues (hypoxia).
- Skin reactions such as rash, redness and itching.
- Pain in the muscles (myalgia).
- Infections – including pneumonia, chickenpox or shingles and blood infections (sepsis).
- Excessive fluid retention in the body tissues, resulting in swelling (oedema).
- Blurred vision.
- Low blood pressure.
- Feeling sick, vomiting or abdominal pain.
- Kidney failure.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while being treated with this one, to make sure that the combination is safe.
There may be an increased risk of an abnormal heart rhythm (seen as a 'prolonged QT interval' on a heart monitoring trace or ECG) if arsenic trioxide is used in combination with any of the following medicines:
- antiarrhythmics (medicines to treat abnormal heart beats), eg amiodarone, procainamide, disopyramide, sotalol
- the antihistamines astemizole, mizolastine or terfenadine
- certain antidepressants, eg amitriptyline, imipramine, maprotiline
- certain antimalarials, eg halofantrine, chloroquine, quinine, mefloquine, Riamet
- certain other antipsychotics, eg thioridazine, haloperidol, sertindole, pimozide
- intravenous erythromycin or pentamidine
There may also be an increased risk of an abnormal heart rhythm (seen as a 'prolonged QT interval' on a heart monitoring trace or ECG) if arsenic trioxide is used in combination with medicines that can lower the level of potassium or magnesium in the blood, such as the following:
- diuretics such as bendroflumethiazide or furosemide
There may be an increased risk of side effects if this medicine is used in combination with other medicines which can also suppress bone marrow function and affect blood cell counts, for example other chemotherapy medicines, or the antipsychotic clozapine.
Vaccines may be less effective in people receiving chemotherapy. This is because chemotherapy medicines reduce the activity of the immune system and can prevent the body forming adequate antibodies. Live vaccines should be postponed until at least six months after finishing chemotherapy because they may cause infection. Live vaccines include the following: oral polio; rubella; measles, mumps and rubella (MMR); BCG; chickenpox; yellow fever and oral typhoid vaccines.
Other medicines containing the same active ingredient
There are currently no other medicines available in the UK that contain arsenic trioxide as the active ingredient.