Chemotherapy induced nausea and vomiting is still one of the most feared side effects. However, there are a number of medications and techniques to control this side effect. Nausea and vomiting are controlled by an area in the brain called vomiting center that is stimulated to cause nausea by the nerves in the gut. Some of the reasons of chemotherapy induced nausea and vomiting are-

Treatments

• Some chemotherapy drugs affect the vomiting center and cause nausea and vomiting.
• Radiation given to the brain, stomach, bowel or liver leads to nausea and vomiting.
• Hormonal therapies sometimes cause nausea.

Physical reasons

• High levels of calcium in the blood can cause nausea and vomiting.
• Raised pressure within the brain affects the vomiting center and cause vomiting.
• In case of liver malfunction, waste products build up in the blood lead to nausea and vomiting.
• Constipation sometimes causes nausea and vomiting.
• Bowel that is blocked by certain pelvic or abdominal cancers causes vomiting.

Emotional reasons

• Anxiety about the cancer or treatment can cause nausea
• Certain situations, previous sessions of chemotherapy, sight of certain foods, strong odors, etc can cause anticipatory nausea i.e. nausea is triggered even before the treatment begins.

Anti-emetics or Anti nausea Medications

There are various drugs or a combinations of drugs used for controlling nausea and vomiting-

5HT3 Inhibitors- These drugs mostly given along with steroids. They block a chemical called serotonin (5HT) that and causes sickness. Some of these drugs are granisetron, ondansetron and tropisetron.

Palonosetron- is a 5HT3 inhibitor in the form of an injection.

Steroids- control sickness in patients with advanced cancer. Dexamethasone is a commonly used steroid.

Metoclopramide - is a drug that empties the stomach as is used as a suppository.

Prochlorperazine- acts on the vomiting center in the brain. This tablet dissolves in the mouth. This is used only if other drugs have not worked. Drug chlorpromazine also works in the same way.

Anti-histamine drugs- are commonly used as anti sickness drug. Cyclizine is an anti-histamine drug.

Sedative drugs- Haloperidol is a sedative drug used in low doses to control sickness Levomepromazine is one more sedative that works in the same manner. However these drugs are used only in advanced cancers and if other drugs are not working. They are taken as tablets. A small pump called a syringe driver is used if the patient has difficulty in swallowing.

Anti-anxiety drug- Lorazepam is an anti-anxiety drug used along with some anti-emetic drug to control nausea.

Neurokin 1 (NK1) inhibitor- NK1 inhibitors are recent drugs that block a chemical in the body that causes nausea. These are given with steroids and a 5HT3 inhibitor to control nausea especially in case of treatment with the chemotherapy drug called cisplatin.

Side Effects of Anti Nausea Drugs

Constipation- Aprepritant, fosaprepitant (both NK 1 inhibitors), granisetron, ondansetron, palonosetron and tropisetron cause constipation . It is essential to drink plenty of fluids and a high fiber diet. Laxatives could be taken if required and as prescribed.

Headaches- Aprepritant, fosaprepitant, Granisetron, ondansetron, palonosetron and tropisetron cause headaches.

Fatigue and weakness- Cyclizine, chlorpromazine, haloperidol, levomepromazine, palonosetron and lorazepam cause drowsiness.

Sleeplessness or insomnia- Dexamethasone causes insomnia

Jerks or Spasms- Metoclopramide causes muscle spasms in different parts of the body like face, neck and shoulders.

Tips to Control Nausea and Vomiting

• Avoid fried foods and food with strong smell.
• Eat small, light and frequent meals.
• Peppermint, ginger or candies help in certain cases.
• Practice relation techniques like meditation, self-hypnosis, imagery, etc.
• Acupuncture and acupressure are alternative techniques that are effective to reduce nausea.

Chemotherapy induced nausea and vomiting can be controlled with various drugs although drugs also have certain side effects. However, it is important be mentally prepared for the treatment especially if the reason is emotion driven.