Anti-Cancer Drugs - NEET PG Pharmacology

Anti-cancer drugs are an important topic for NEET PG preparation as they are a key aspect of oncology and form a significant part of the syllabus in postgraduate medical exams. 

Read this medical notes blog for a quick overview of the topic and enhance your NEET PG Preparation. Also, stay tuned to our blog for notes on high-yield topics from Pharmacology.

Anti-Cancer Drugs

Any medication that is successful in treating malignant or cancerous disease is referred to as an anticancer drug, often known as an antineoplastic drug. Alkylating agents, antimetabolites, natural products, and hormones are a few of the main groups of anticancer medications. 

Additionally, a variety of medications that do not belong to such classes yet have anticancer action are utilised to treat malignant diseases. Although it is more true to say that chemotherapy refers to the use of chemical substances to treat disease in general, the term chemotherapy is usually used synonymously with the use of anticancer medications.

• Anti-cancer drugs can be divided into 2 categories. They are:
  • Cytotoxic drugs
  • Targeted drugs

What are the Cytotoxic drugs?

• They destroy all kinds of cells and not only the cancer cells. Some of their side effects include- 
  • Hyperuricemia.
  • Bone marrow separation.
  • Diarrhea
  • Alopecia

Cytotoxic drugs can be divided into three categories.

• S-phase specific
• M-phase specific
• Non-specific

Non-specific drugs

1. Alkylating Agents

• The drugs in this category can be remembered by the code “If Bus Not Present Take My Cycle”:
  • If - Ifosfamide
  • Bus - Busulfan 
  • Not - Nitrosoureas
  • Present - Procarbazine
  • Take - Temozolomide 
  • My - Melphalan 
  • Cycle - Cyclophosphamide 
• Ifosfamide and cyclophosphamide can cause hemorrhagic cystitis as a side effect.
• The active metabolite of cyclophosphamide is 4-hydroxycyclophosphamide. 

2. Platinum Compounds
   • Drugs in this category include:
     • Cisplatin
     • Carboplatin
     • Oxaliplatin 

Cisplatin sensitizes the body to radiotherapy. Hence the same amount of radiation can cause more toxicity if the person is under the administration of cisplatin.

3.  Miscellaneous Drugs 
   • Bleomycin is an example of an anti-cancer drug. It is metabolized by bleomycin hydrolase which is deficient in skin and lungs. Hence it can cause flagellated pigmentation of skin as a side effect. Whereas in the lungs, it can cause pulmonary fibrosis. 
   • The side effects of cytotoxic drugs include:

• Cisplatin
  • Autotoxicity
  • Vomiting 
  • Nephrotoxicity
• Vincristine
  • SIADH release. 
  • They act in the periphery leading to peripheral neuropathy.
• Bleomycin/Busulfan 
  • Can cause pulmonary fibrosis. 
• Doxorubicin/Daunorubicin/Epirubicin 
  • Cause cardiotoxicity. 
• 6-mercaptopurine
  • Hepatotoxic
• Cyclophosphamide
  • Causes hemorrhagic cystitis which can be prevented by using mesna. 

Also Read: Bronchial Asthma Treatment - NEET PG Pharmacology

What are the Targeted Anti-Cancer Drugs?

Monoclonal antibodies

• Targeted drugs can be monoclonal antibodies like
  • Cetuximab: Used in colorectal carcinoma
  • Rituximab: Is used in Non-Hodgkin's Lymphoma (NHL) and Chronic lymphoid leukemia. 
  • Trastuzumab: Is used to treat breast cancer. It is a cardiotoxic drug.
• Immune checkpoint inhibitors
  • It is a group of monoclonal antibodies recently developed. T-cells which are programmed to kill the cancer cells have programmed death ligate (PDL-I) on their surface and the cancer cells have a Programmed death receptor on its surface. Checkpoints are certain kinds of proteins synthesized by immune system cells like cancer cells and T-cells.
  •  Checkpoint proteins help to tamper down the strength of our immune response and sometimes prevent the T-cells from killing the cancer cells in our body. When these checkpoints are blocked, the T-cells can kill the cancer cells more easily.
  •  Hence, if the interaction between the T-cells and cancer cells which leads to the prevention of the latter from killing the former is inhibited, cancer cells can be destroyed. There are drugs which can bind to PD-I and PDL-I. The drugs which bind to PD-I can be remembered by the code “PeNCil”:
    • Pe- Pembrolizumab
    • N- Nivolumab 
    • C- Cemiplimab
  • The drugs which bind to the ligand can be remembered by the code “L A A D” (L for ligand):
    • A - Atezolizumab
    • A - Avelumab
    • D - Durvalumab 
  • These drugs can be used for the treatment of many types of cancers; especially, pembrolizumab and nivolumab.
  • Pembrolizumab is used to treat endometrial cancer apart from all other types of cancers for which it is administered. 
  • Cemiplimab is used for squamous cell carcinoma of skin.
  • Atezolizumab and durvalumab are used for the treatment of urothelial carcinoma. 
  • Avelumab is used for the treatment of Merckel cell carcinoma.

Also Read: NEET PG 2023: High-Yield Topics for Pharmacology

Tyrosine Kinase Inhibitors

The name of the drugs belonging to this category end with “NIB” and all of them are effective when administered orally. Some of the important tyrosine kinase inhibitors are as following: 

1. Used for chronic myeloid leukemia (can be remembered by the code “I N D”):
   • I - Imatinib
   • N - Nilotinib
   • D - Dasatinib 
   • Imatinib is the DOC for CML.
2. Used in lung carcinoma. The name of the drugs can be remembered by the code “E C G”:
   • E - erlotinib
   • C - Ceritinib
   • G - Gefitinib
3. Used for Renal cell carcinoma (RCC). Drugs can be remembered by the code “P A S S”:
   • P- Pazopanib
   • A - Axitinib
   • S - Sorafenib 
   • S - Sunitinib 
4.  For hepatocellular carcinoma (HCC), the DOC is sorafenib.
5. For breast cancer, the DOC is lapatinib.
6. Gastrointestinal stromal tumor (GIST). Drugs used can be remembered by the code “S I R”:
   • S- Sunitinib
   • I - Imatinib
   • R - Regorafenib 
   • Imatinib is the DOC for GIST.

What are Proteasome inhibitors?

This category of drugs is used in multiple myeloma. The name of the drugs end with “ZOMIB” like:

• Bortezomib
• Ixazomib
• Carfilzomib

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