Arsenic Trioxide (Trisenox®)

Last Modified: August 21, 2011

Pronounced: AR-se-nik trye-OX-ide
Classification: Antineoplastic Agent

About Arsenic Trioxide

Arsenic trioxide is a form of the naturally occurring compound arsenic. It has been used by health practitioners (particularly in Asia) for hundreds of years. It is safe when given in small doses by experienced healthcare professionals. It seems to work against cancer by causing cancer cells to self-destruct; this is also known as apoptosis.

How to Take Arsenic Trioxide

Arsenic Trioxide is given by intravenous (into a vein) infusion, over 1-2 hours. For people who experience reactions during the infusion (such as rash, shortness of breath, and cough), the infusion can be slowed down and run over 4 hours.

Possible Side Effects of Arsenic Trioxide

There are a number of things you can do to manage the side effects of Arsenic Trioxide. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Increased White Blood Cell Count

This is also called hyperleukocytosis. Generally, it does not cause any problems, nor does it require stopping the treatment. Your healthcare provider will monitor your white blood count during treatment.

Differentiation Syndrome

This is a syndrome resulting from the changes arsenic trioxide causes to blood cell production in patients with leukemia. Symptoms of differentiation syndrome include: fever (temperature >100.5), sudden weight gain, bone or joint pain, and fluid build-up around the heart, lungs, and/or chest, causing shortness of breath or difficulty breathing. This syndrome is treated with high doses of steroids (like prednisone) and diuretics (fluid pills). Your healthcare providers will monitor for these signs or symptoms, but it is also important for you to tell your doctor or nurse promptly if you experience any of these symptoms. You will be asked to weigh yourself every day during the first few weeks of therapy, and to report any increases in weight correctly.

Abnormal Heart Rhythms

Arsenic trioxide can cause changes in your heart rhythm. This will be monitored by electrocardiogram (ECG). It is important for your potassium and magnesium levels to be normal, so these will also be monitored, and you may need to take supplemental potassium or magnesium. Be sure to let your doctor know if you have any history of heart rhythm abnormalities, and list all the medications you are taking (both prescription and over the counter).

Nausea and/or Vomiting

Take anti-nausea medications as prescribed. If you continue to have nausea or vomiting, notify your doctor or nurse so they can help you manage this side effect. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms. Read the Nausea & Vomiting Tip Sheet for more suggestions.

Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.


Your oncology team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals and seeds. Soluble fiber is found in some foods that absorbs fluid and can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange and grapefruit sections, boiled potatoes, white rice and products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses on non-alcoholic, un-caffeinated fluid a day to prevent dehydration. Read Low Fiber Diet for Diarrhea for more tips.

Muscle or Joint Pain/Aches and Headache

Your doctor or nurse can recommend medication and other strategies to relive pain. You can also view OncoLink's page on pain management.

Peripheral Neuropathy (Numbness or Tingling in the Hands and/or Feet)

Peripheral neuropathy is a toxicity that affects the nerves. It causes a numbness or tingling feeling in the hands and feet, often in the pattern of a stocking or glove. This can get progressively worse with additional doses of the drug. In some people, the symptoms slowly resolve after the drug is stopped, but for some it never goes away completely. You should let your healthcare provider know if you experience numbness or tingling in the hands and feet, as they may need to change the doses of your medication. See OncoLink's section on peripheral neuropathy for tips on dealing with this side effect.


Insomnia is a common problem for people with cancer and was reported in clinical trials of arsenic trioxide. See this OncoLink article on insomnia for helpful tips.


See OncoLink's section on fatigue for helpful tips on dealing with this side effect.

Other Side Effects

Abdominal pain, increase in blood glucose (blood sugar), rash, and itching.


Click on any of these terms for more related articles


Breaking news: Supreme Court votes to uphold Affordable Care Act Subsidies
by Christina Bach, MSW, LCSW, OSW-C
June 26, 2015