Arsenic trioxide
Say it: AR-seh-nik try-OX-ide · Brand names: Trisenox
Arsenic trioxide is a medicine that treats a type of blood cancer called acute promyelocytic leukemia.
What it is
In this leukemia, young blood cells get stuck and cannot grow up into normal cells. Arsenic trioxide breaks down the faulty protein that keeps them stuck. This lets the cells mature or die, so healthy blood cells can come back.
Often used for
- acute promyelocytic leukemia (a type of acute myeloid leukemia), as a first treatment together with tretinoin
- acute promyelocytic leukemia that came back or did not respond to other treatment
How you get it
You get it through a needle into a vein. Each dose usually takes about 2 hours, and sometimes longer. At first it is often given every day, then on a set number of days each week during later treatment. Your schedule may be different.
Common side effects and what helps
- Feeling tired. Rest when you need to and take short walks.
- Upset stomach or throwing up. Medicine for nausea can help, so ask your team.
- Headache. Ask your team which pain medicine is safe for you.
- Swelling in the hands, feet, or legs. Tell your team, especially if it comes on fast.
- Cough or a sore throat. Sip fluids and tell your team if it gets worse.
- High blood sugar. Your team will check it with blood tests.
- Rash or itchy skin. Use a gentle, unscented lotion.
- Diarrhea. Drink plenty of fluids and tell your team if it does not stop.
Call your care team right away if you have
- Trouble breathing, a new cough, or chest pain
- A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher
- Fast weight gain or swelling that comes on quickly
- Feeling faint, a racing or pounding heartbeat, or passing out
- Confusion, trouble walking, vision changes, or feeling very sleepy
- Bleeding or bruising that is unusual for you
Before you start, tell your team
- If you have heart problems or have ever had an abnormal heart rhythm
- All medicines, vitamins, and herbs you take, since some can affect your heart rhythm
- If you have kidney problems
- If you are pregnant, may become pregnant, or are breastfeeding. This medicine can harm an unborn baby.
- If you have trouble eating or have lost a lot of weight
Good to know
- A serious reaction called differentiation syndrome can happen, often in the first weeks. Signs include fever, trouble breathing, fast weight gain, and swelling. It can be treated if caught early.
- This medicine can change your heart rhythm. You will have heart tracing tests (electrocardiograms) before and during treatment.
- You will have frequent blood tests to check potassium, magnesium, calcium, blood sugar, and your blood counts.
- A rare brain problem linked to low vitamin B1 (thiamine) can happen. Your team may check for it or give you vitamin B1.
- Both men and women should use reliable birth control during treatment and for a time after. Ask your team how long.
Questions to ask
- How long will each part of my treatment last?
- What signs of differentiation syndrome should I watch for?
- How often will I need heart tests and blood tests?
- Are any of my current medicines a problem with this one?
Part of these treatment plans
Side effect guides
Sources
Quick answers
- What is Arsenic trioxide?
- Arsenic trioxide is a medicine that treats a type of blood cancer called acute promyelocytic leukemia. Brand names: Trisenox.
- What is Arsenic trioxide used for?
- acute promyelocytic leukemia (a type of acute myeloid leukemia), as a first treatment together with tretinoin; acute promyelocytic leukemia that came back or did not respond to other treatment.
- How is Arsenic trioxide given?
- You get it through a needle into a vein. Each dose usually takes about 2 hours, and sometimes longer. At first it is often given every day, then on a set number of days each week during later treatment. Your schedule may be different.
- What are the common side effects of Arsenic trioxide?
- Feeling tired. Upset stomach or throwing up. Headache. Swelling in the hands, feet, or legs. Cough or a sore throat. High blood sugar. Rash or itchy skin. Diarrhea.
- When should I call my care team while taking Arsenic trioxide?
- Trouble breathing, a new cough, or chest pain; A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher; Fast weight gain or swelling that comes on quickly; Feeling faint, a racing or pounding heartbeat, or passing out; Confusion, trouble walking, vision changes, or feeling very sleepy; Bleeding or bruising that is unusual for you.
- Which chemotherapy plans include Arsenic trioxide?
- ATRA and ATO.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.