How Do Chemotherapy Drugs Work And What Are Their Side-Effects

Posted On Dec 24, 2019

Department of

Manipal Hospitals

Cancer is one of the leading causes of death all over the world. There are various types of cancer affecting different body parts in men and women. Each type of cancer has its own treatment options that depend on severity. Chemotherapy is one such treatment option, usually given in severe stages of cancer.

Chemotherapy refers to the use of medicines or drugs to treat cancer. The primary goal of the treatment is to stop or slow the growth of cancer cells. It is considered a systemic therapy, which means that it affects your entire body. These drugs target the malicious cells which grow rapidly but sometimes may also affect the healthy cells. There are different types of chemotherapy.


There are different types of chemotherapy drugs that are used to treat cancer. They are classified based on their chemical and structural properties and the mechanism of their action on cancer cells.

Alkylating agents: These agents are more effective in the resting phase of the cell. These types of drugs are cell-cycle non-specific, and several types of these agents are used in chemotherapy treatments. They include mustard gas derivatives (mechlorethamine, ifosfamide, and chlorambucil), ethylenimines (thiotepa and hexamathylmelamine), alkyl sulfonates (busulfan), and nitrosoureas (carmustine, lomustine), etc.

Side effects

You may experience side effects like nausea and vomiting, symptoms of anemia, infection, and bleeding.

Plant alkaloids: It is a type of chemotherapy treatment that is derived from different types of plants. These types of drugs are cell-cycle specific and attack the cells during various phases of division. They include vinca alkaloids (vincristine, vinblastine, and vinorelbine), taxanes (paclitaxel and docetaxel), podophyllotoxins (etoposide and teniposide), etc.

Side effect:

You may experience side effects like nausea and vomiting, hair loss, mouth sores, headaches, and constipation.

Antitumor antibiotics: These are the types of chemo treatments that are made from natural substances produced by species of the soil fungus streptomyces. These drugs act during the multiple phases of the cell cycle and are considered cell-cycle specific. There are different types of antitumor antibiotics which include anthracyclines (doxorubicin, daunorubicin), chromomycin (dactinomycin and plicamycin), and miscellaneous (mitomycin and bleomycin).

Side effects

The common side effects of these drugs are nausea and vomiting, loss of appetite, hair loss, numbness or tingling sensation in your fingers, eye problems, skin rash, darkening or lightening of the skin, and fever, etc.

Antimetabolites: This type of chemotherapy treatment is similar to normal substances within the cell. These are cell-cycle specific and attack at a very specific phase of the cycle. They are classified into different types based on the substance they interfere with. They are folic acid antagonist (methotrexate), pyrimidine antagonist (5-fluorouracil, floxuridine, etc.), purine antagonist (6-mercaptopurine and 6-thioguanine), and adenosine deaminase inhibitor (cladribine, fludarabine, etc.).

Side effects

You may experience side effects like tiredness, nausea and diarrhea, mouth sores, hair loss, abnormal liver function, anorexia, and anemia, etc.

Topoisomerase inhibitors: These drugs interfere with the action of topoisomerase enzymes. They are classified into different types which include: topoisomerase I inhibitors (irinotecan and topotecan) and  topoisomerase II inhibitors (amsacrine, etoposide, etoposide phosphate, etc.)

Side effects

You may experience side effects like fever, extreme weakness or tiredness, redness, and sores or ulcers in the mouth, etc.

Common uses of chemotherapeutic drugs

Chemotherapy drugs are used to kill cancer cells. But these drugs often kill the healthy cells in the gastrointestinal tract, immune system, and bloodstream. They are also used to treat diseases conditions other than cancer.

They are used to:
  • Control the symptoms of rheumatoid arthritis
  • Treat and control the symptoms of lupus (an autoimmune disease that causes chronic inflammation and may affect any of the body)
  • Treat multiple sclerosis


Chemotherapy is ultimately a type of cancer treatment aimed at curing the patient. It is associated with many side effects but can be managed effectively through medications and by following the doctor’s instructions.

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