Chemotherapy Emetogenic is the chemotherapy induced nausea and vomiting or CINV. This is the symptom that causes concern to most patients undergoing chemotherapy. This could lead to excessive vomiting, dehydration and weakness that in turn could adversely impact the quality of life.

There are many anti emetics in chemotherapy. Many of them are given prior to the treatment to prevent nausea, yet some patients still face acute symptoms of nausea, loss of appetite, etc.

Apart from the anti emetic medications, dosage of the drugs can be adjusted to reduce this symptom as more amount of drug leads to more pronounced side effects, whichever they may be. A new class of anti emetic agents that are the selective antagonists of the type 3 serotonin receptor are now being recommended although there are various risk factors and cost issues.

Some of these risk factors are related to patient i.e. the age, gender, alcohol consumption and previous treatment with chemotherapy if any. Some of the risk factors are related to the drugs that are administered.

Drugs Associated with Chemotherapy induced Nausea and Vomiting

Emesis could be during chemotherapy, before or after the treatment due to various physiological and psychological reasons. Emesis could be delayed or immediate. Emesis is categorized into various risk types depending upon the drugs used and patient population. Some of the drugs responsible for nausea or emesis depending on the dosage are-

High-risk emesis occurs in more than 90% of patients with the use of following drugs-

• Cisplatin
• Mechlorethamine
• Streptozotocin
• Cyclophosphamide
• Carmustine
• Dacarbazine
• Dactinomycin

Moderate risk emesis with the following drugs occurs in 30% to 90% of the patients-

• Carboplatin
• Cyclophosphamide
• Daunorubicin
• Doxorubicin (Adriamycin)
• Epirubicin
• Idarubicin
• Oxaliplatin
• Cytarabine
• Ifosfamide
• Irinotecan

Low risk emesis with the following drugs is seen in 10% to 30% of patients-

• Mitoxantrone
• Paclitaxel (Taxol).
• Docetaxel (Taxotere).
• Mitomycin
• Topotecan
• Gemcitabine
• Etoposide
• Pemetrexed
• Methotrexate
• Cytarabine
• Fluorouracil
• Bortezomib
• Cetuximab (Erbitux).
• Trastuzumab

Occurrence of Emesis

Cisplatin drug when administered triggers the release of these 5-HT3 receptors from the enterochromaffin cells that causes nausea and vomiting. However, this cisplatin induced nausea can be managed by the serotonin antagonists.

Stimulation of the CTZ also triggers CINV i.e. chemotherapy induced nausea and vomiting. CTZ is stimulated by certain substances in the blood or cerebrospinal fluid. Dopamine substances like phenothiazines and butyrophenones prevent the nausea triggered due to CTZ.

Cerebral cortex stimulates nausea and vomiting that is called anticipatory nausea. Some people develop nausea with the very thought of undergoing chemotherapy. There could be several reasons for this kind of nausea. For instance, a previous experience with chemotherapy, fear, anxiety, etc could all cause anticipatory nausea. Normally, dronabinol or lorazepam could be recommended in such cases. This could also be treated with behavioral therapies.

Delayed emesis develops almost after 1 or 2 days post treatment. In these cases, corticosteroids like dexamethasone in combination with metoclopramide or phenothiazines are usually recommended.

Chemotherapy emetogenic can now be treated effectively either with the help of medications of alternative therapies. Although nowadays there many new drugs developed that are used in targeted chemotherapy or biological therapy which are effective in treating cancer and have reduced side effects. Some of these drugs are induced in the targeted area and restricted from entering the bloodstream. Hence, the side effects are reduced. In spite of all the advances and the reduced side effects, withstanding chemotherapy and its debilitating side effects is still not a cake walk. Some of them sail through it while most people have a hard time dealing with it even if they survive. The good part is that chemotherapy and its side effects like nausea are not as dreadful as they were till a few years ago. It would be of great help if you ask your health care provider to give you some more information about treating cancer with chemotherapy.