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Arsenic Trioxide

(ar-sen-ik try-ox-ide)

Trade/Other Name(s): Trisenox

Why would this drug be used?

Arsenic trioxide is used to treat certain types of leukemia.

How does this drug work?

This form of arsenic is an antineoplastic (anti-cancer) drug, although its action is not completely understood. Arsenic trioxide appears to cause changes in cancer cells that make them die. It also appears to correct the gene responsible for making the flawed protein (called the PML-RAR fusion protein) that causes acute promyelocytic leukemia (APL). Arsenic trioxide is used to treat APL.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have ever had heart problems such as uneven heartbeat, heart block, heart failure, or abnormal EKG. People with these problems have a higher risk of dangerous heart rhythms while taking arsenic trioxide.
  • If you have had low magnesium or potassium levels in your blood. This can increase your risk of dangerous heart rhythms while taking arsenic trioxide.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause birth defects if either the male or female is taking it at the time of conception or during pregnancy. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breast-feeding. The drug passes into breast milk and can harm the baby.
  • If you think you might want to have children in the future. Some drugs can cause sterility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

  • Arsenic trioxide may raise your risk of heart rhythm problems even more if you are taking other drugs that affect the body's mineral (electrolyte) balance or that affect the heart rhythm, such as these:
  • diuretics (water pills)
  • antibiotics such as ciprofloxacin (Cipro), levofloxacin (Levaquin), sparfloxacin (Zagam), moxifloxacin (Avelox), erythromycin (E.E.S., E-Mycin, Erythrocin), clarithromycin (Biaxin), or pentamidine (Pentam, NebuPent)
  • anti-fungal drugs (amphotericin B)
  • heart rhythm drugs such as amiodorone (Cordarone, Pacerone), disopyramide (Norpace), ibutilide (Corvert), procainamide (Procan, Pronestyl), quinidine (Quinidex, Cardioquin), sotalol (Betapace), dofetilide (Tikosyn)
  • mental health drugs such as haloperidol (Haldol), thioridazine (Mellaril), pimozide (Orap), mesoridazine (Serentil), chlorpromazine (Thorazine)
  • methadone (Dolophine, Methadose)
  • the anti-nausea drug droperidol (Inapsine)
  • anti-malaria drugs halofantrine (Halfan) and chloroquine (Aralen)
  • bepridil (Vascor), a drug for angina or heart pain

Some people have an increased risk of bleeding during treatment with this drug (see "Precautions" section below). Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with arsenic trioxide. These include:

  • vitamin E
  • non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • warfarin (Coumadin)
  • ticlopidine (Ticlid)
  • clopidogrel (Plavix)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what's in the medicines you take.

Check with your doctor, nurse, or pharmacist about other medicines, vitamins, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Arsenic trioxide is infused into a vein (IV) over a 1 to 4 hour period. The first treatments (called induction) are given every day until the leukemia cells in the bone marrow disappear, up to 60 treatments. Between 3 and 6 weeks after induction, further treatment (called consolidation) is given 5 days a week for up to 5 weeks. Your dose depends on your weight.


Arsenic trioxide can increase the time it takes for the heartbeat impulse to pass through the heart. You will have an electrocardiogram (EKG) before you start treatment with arsenic trioxide, and this may be repeated during the treatment. You will also have blood tests to make sure that the mineral balance in the blood (electrolytes such as potassium, calcium, and magnesium) and the kidney function tests are normal. If they are abnormal, or if the EKG shows changes, your treatment will be stopped until the abnormality is corrected. Keep all your appointments for lab tests and doctor visits.

Call the doctor or nurse right away if your heart rate speeds up or becomes irregular, if you have chest pain, if you pass out (faint), or have a seizure.

If you have acute promyelocytic leukemia (APL), the drug may cause a problem known as APL differentiation syndrome. It begins with fever, shortness of breath or trouble breathing, and rapid weight gain. You need to watch for and report any of these symptoms right away so that treatment can be started. This problem can cause death if not treated.

In some people, this drug may lower the platelet count in the weeks after it is given, which can increase the risk of bleeding. Speak with your doctor before taking any drugs or supplements that might affect your body's ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

Call your doctor right away if you have symptoms of high blood sugar, such as extreme thirst or hunger, passing urine frequently, weakness, or blurred vision.

Call your doctor or nurse right away if you notice a rash, fever, shaking chills, low urine output, or trouble breathing.

Arsenic trioxide is a known cancer-causing agent. If you are getting this drug, your doctor feels the risk of taking the drug is outweighed by the risk of what might happen if you do not get it. You may want to discuss these risks with your doctor.

Avoid pregnancy during and for at least a few months after treatment, since exposure to this drug may harm the fetus. Talk with your doctor about this.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • nausea
  • vomiting
  • poor appetite
  • constipation
  • pain in the belly (abdomen)
  • headaches
  • dizziness
  • tiredness (fatigue)
  • trouble sleeping
  • cough
  • fever with shaking chills (rigors), hives, trouble breathing*
  • skin rash or redness*
  • itching
  • high white blood cell count
  • low blood levels of potassium or magnesium*
  • high sugar level in the blood*

Less Common

  • heartburn (sour stomach)
  • dry mouth
  • low red blood cell count (anemia) with shortness of breath and low energy
  • low platelet count with increased risk of bleeding*
  • low white blood cell count with increased risk of infection
  • chest pain*
  • changes in the electrical impulses of the heart, which can slow the heartbeat*
  • aching of muscles and bones
  • numbness or tingling of hands or feet
  • tremor
  • swelling in the face or eyes
  • too little oxygen in the blood
  • fluid around the lungs or heart
  • breathing problems*
  • bleeding or bruising
  • diarrhea
  • wheezing
  • pain, redness, and swelling at injection site
  • high blood levels of potassium or calcium*
  • low blood sugar
  • increased blood levels of liver function tests


  • irregular heartbeat, which can cause death*
  • swollen or tender belly (abdomen)*
  • weight gain*
  • confusion
  • fainting*
  • seizures
  • coma
  • darkening of skin
  • serious allergic reaction with symptoms like flushing, itching, hives, dizziness, trouble breathing or swallowing
  • death from heart rhythm problems or other causes

*See "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2000

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 02/11/2010
Last Revised: 02/11/2010