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When discussing potential anticancer treatments with your doctor, you may hear the term “alkylating agent.”

Also called cytotoxic agents or antineoplastic drugs, alkylating agents are types of chemotherapeutic drugs. They treat certain forms of cancer by stopping tumor DNA from dividing and replicating.

While alkylating agents are among the most commonly used chemotherapies, they also pose a risk of wide-ranging side effects.

Read on to learn about the different classes of alkylating agents and drug types, as well as risks and efficacy rates to consider.

Alkylating agents are used in treating various forms of cancer, but they tend to work best in slow-growing cancers, such as:

According to the National Cancer Institute (NCI), these anticancer drugs were among the first of their kind. Also, they remain the most commonly used chemotherapeutic drug types.

Alkylating agents work by destroying the DNA in cancer cells. This is done by replacing alkyl groups with hydrogen atoms in the DNA so the cells can’t repair themselves. As a result, the lack of functioning DNA prevents cancer cell division and replication.

To help minimize the risk of side effects, oncologists typically give the lowest, most effective dosage.

While many alkylating agents are administered intravenously (through an IV) or via injection, some types are given orally.

There are six major classes of alkylating agents, with specific drugs belonging to each class:

Alkyl sulfonates (busulfan)

Busulfan is an injectable alkylating agent mainly used in the treatment of chronic myeloid leukemia (CML). This is a strong drug that causes myelosuppression, a side effect that lowers platelets and blood cell counts.

As a result of myelosuppression, your care team will need to monitor your blood counts carefully for related complications such as anemia and low platelets (thrombocytopenia).

Ethylenimine and methylenamine derivatives (altretamine, thiotepa)

Also used as injections, these types of alkylating agents are primarily used in the treatment of breast and ovarian cancers. Thiotepa, one brand-name drug in this type, may also be used to treat bladder cancer.

Myelosuppression, or decreased bone marrow activity, is possible with these injections. Other side effects may include reproductive effects such as the absence of menstruation, gastrointestinal issues, and more.

Nitrogen mustards (cyclophosphamide, and others)

Nitrogen mustards are primarily used in the treatment of lymphoma. This includes Hodgkin’s disease.

Several drugs are considered nitrogen mustards, including:

Certain types, such as cyclophosphamide, may be taken orally via tablet form. Valchlor, another type, is applied topically after using other skin-directed treatments.

Nitrogen mustards may be used to help prevent cancer cells from replicating during any stage of the cell cycle.

Along with myelosuppression, other risks associated with nitrogen mustards include an increased risk of infection, as well as bone marrow diseases.

Nitrosoureas (carmustine, lomustine)

There are two types of nitrosoureas: carmustine injections and lomustine (Gleostine) oral tablets. Oncologists may prescribe these to help treat brain tumors.

Potential side effects to consider include myelosuppression, liver damage, and pulmonary toxicity, which affects the lungs.

Platinum-containing antineoplastic agents (carboplatin, cisplatin, oxaliplatin)

Also called platinum coordinating complexes, these drugs work differently from other alkylating agents by destroying the DNA in cancer cells without the use of alkyl groups.

While these agents are primarily used to treat ovarian cancers, oxaliplatin injections are used in stage 3 colon cancer. The other two agents in this category, carboplatin and cisplatin are also delivered via injection.

Your doctor will talk with you about the potential risks of these agents, such as neurotoxicity, gastrointestinal effects, and myelosuppression. Anaphylaxis (a severe allergic reaction) is also possible with oxaliplatin.

Triazenes (dacarbazine, procarbazine, temozolomide)

Triazenes are used to treat a variety of cancers, including brain tumors, melanoma, and Hodgkin’s disease. While dacarbazine and procarbazine are used in injection or intravenous (IV) solutions, temozolomide is a capsule taken by mouth.

Risks associated with triazenes include liver and bone marrow damage, myelosuppression, and severe gastrointestinal symptoms, such as vomiting.

Alkylating agents are a class of drugs among the most commonly used in chemotherapy, either alone or in combination with other therapies. This is due to the fact that they have a long track record of effective results.

Your doctor will recommend a class based on the type of cancer you have, as well as the stage. Overall efficacy and side effects of the anticancer drug will also be considered.

It’s important to talk with your doctor about all types of anticancer drugs available, including chemotherapies. Depending on the type of cancer you have, other chemotherapeutic options may include:

  • antimetabolites
  • antitumor antibiotics
  • plant alkaloids
  • combination chemotherapy

Besides chemotherapy, other anticancer treatment options may include:

Alkylating agents help destroy DNA in cancer cells. Unfortunately, the same processes that prevent cancer cells from multiplying also affect healthy cells in the body. This leads to some of the notorious side effects chemotherapy drugs are known for.

The most common side effects of alkylating agents include:

With alkylating agents, there’s also an increased risk of bone marrow damage, particularly at high doses. This could lead to leukemia in some people.

To help treat side effects, an oncologist may recommend one or more of the following:

Using the least, but most effective dose possible can help reduce your risk of side effects. There are also other types of chemotherapy drugs to maximize anticancer treatment.

Alkylating agents are just one type of chemotherapeutic class considered in anticancer treatment. There are several subtypes and related drugs in these agents, and they work by destroying cellular DNA to prevent cancer cells from multiplying.

Your doctor can help you determine if alkylating agents are right for you, based on the cancer type and stage, as well as the potential risks and side effects.