AC (Adriamycin and cyclophosphamide) is a common chemotherapy regimen usually given for localized breast cancers.

AC is a combination of two chemotherapy medicines:

Doxorubicin is a type of chemotherapy medicine called an anthracycline. Cyclophosphamide is a type of chemotherapy medicine called an alkylating agent.


How AC works

Both doxorubicin and cyclophosphamide damage the DNA inside cancer cells so they can’t divide, which causes them to die. Doxorubicin stops damaged cancer cells from continuing to grow, while cyclophosphamide stops cancer cells from reproducing.

The medicines attack the cancer cells at different stages of their growth:

  • Doxorubicin works at any point in the cell cycle.
  • Cyclophosphamide works when the cells are in their resting phase (not dividing)

Who gets AC

AC is used to early-stage breast cancer. It is a very common combination, whether or not the cancer is in the lymph nodes. It is often, but not always, followed by paclitaxel (Taxol). This is called AC-Taxol. Another option is AC given in combination with docetaxel (Taxotere), called TAC.

AC is sometimes also recommended to treat local recurrence, or breast cancer that has returned at or near the original site.

You and your doctor will discuss the best chemotherapy treatment for your situation.


How AC is given

AC can be given after surgery as an adjuvant therapy, or before as a neoadjuvant therapy.

The medicines are usually given by vein on the same day, followed by a rest period of two or three weeks. When given every two weeks, your doctor may call this schedule dose-dense AC chemotherapy. This cycle is usually repeated four to six times over three to five months.


Side effects and things to remember

Different medicines have different side effects. You may not have every side effect related to each medicine of the combination therapy. Common side effects of AC include:

Less common side effects include:

Before starting AC tell your doctor about any medicines you are taking, including vitamins, herbal supplements, and over-the-counter medicines, to make sure they won’t interfere with your chemotherapy treatment.

You should avoid becoming pregnant while you are receiving AC. Tell your doctor right away if you become pregnant while undergoing treatment.

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. You can also go to our section on side effects for more information.


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Reviewed and updated: December 1, 2023

Reviewed by: Reshma L. Mahtani, DO


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