Antimetabolites for Cancer: Effects, Benefits, Risks

Medically Reviewed by Sabrina Felson, MD on June 07, 2022
3 min read

If you or a loved one has been prescribed an antimetabolite to treat cancer, you’ll want to know all about this type of drug, including the risks and benefits. Antimetabolites are a form of chemotherapy drug. They’re one of the most commonly used therapies to treat cancer. And they’re one of the oldest, dating back to the 1940s, when doctors used a medication that’s now considered an antimetabolite to treat children with leukemia.

Antimetabolites are called a “cytotoxic” type of drug because they kill cells. They work by mimicking the molecules that a cell needs to grow. Cells are tricked into taking in the drugs and then using the antimetabolites instead of their normal building blocks of genetic material: RNA and DNA. With the drugs on board, the cells can no longer copy their DNA, so they can’t divide into new cells. Because antimetabolites target cells only as they are dividing, these medications are most effective against tumors that are growing quickly.

Some antimetabolites that are commonly used to treat cancer include:


Antimetabolites are most commonly used to treat leukemias and cancers of the breast, ovary, and the intestinal tract. But since the drugs work to slow the growth of any quickly dividing cell type, they can be used to treat various others cancers, too.

Different antimetabolite drugs are taken in different ways, depending on the drug and the type of cancer being treated.

Some antimetabolites are available as tablets or liquids you take by mouth every day.

Others are given by injection through an intravenous (IV) line that a health care professional inserts into a vein. Often, it’s a specific kind of IV line called a mediport that sits in a large, central vein.

Antimetabolites used for skin cancers are available as creams that you rub on the affected skin are once or twice a day.

The benefit of taking antimetabolite drugs to treat cancer is that the drugs kill cancer cells, which can help you live longer and make your tumor stop growing or shrink.

But antimetabolites don’t work for everyone, and it can be hard for doctors to predict whose tumors will respond to these drugs. Even when antimetabolites first work well, tumors often become resistant to these drugs, which means they eventually don’t work anymore.

Because antimetabolites include a variety of drugs, side effects may differ between drugs. If you’re going to take a particular antimetabolite to treat cancer, you should talk to your doctor about the common side effects of that drug.

In general, side effects found in many antimetabolites include: