Pediatric Oncology
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Basic Oncology

Overview

Radiotherapy Basics

Chemotherapy

Surgery

Investigation

Differential Diagnosis

 

Introduction Venous Access Nausea Pain Control Fluids & DI Low Counts Infection Immunization Dermatitis/Mucositis OtherResourcesReferences

 

 

Emergencies

 

 

Brain Tumors

BM Transplant

Leukemia

Lymphoma

Sarcomas

Renal Tumors

Neuroblastoma

Late Effects

 

 

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Nausea and Vomiting

 

Nausea and vomiting are common side effects of chemotherapy and radiation therapy (RT).

Symptoms can be severe and prolonged.
           
The vomiting center in the medullary lateral reticular formation is responsible for initiating the vomiting reflex. 

• It receives input from various afferent pathways, including visceral sympathetic afferents and midbrain intracranial pressure receptors. 
• Efferent pathways are activated by stimulation in the vomiting center and induce the actual vomiting process. 
• These pathways include the phrenic nerve to the diaphragm, the spinal nerves to the abdominal, and the visceral nerves to the stomach and the esophagus.
• RT-induced vomiting is mediated by both the CTZ (chemoreceptor trigger zone) as well as peripheral mechanisms. 

• Total body, cranial, and abdominal RT are all potentially emetogenic. 
• Nausea and vomiting induced by RT are particularly receptive to 5-HT3 receptor antagonists.         

Other causes of nausea and vomiting include:

• Disease related
  • Vestibular reflexes
  • Raised intracranial pressure
• Chemotherapy related
  • Gastrointestinal obstruction and ileus (VCR)
• Other medication
  • Narcotic administration

 

Prevention of treatment-induced nausea

Prophylactic antiemetic therapy should always be used. This involves:

• blocking receptors for emetic stimulus before stimulation occurs
• continuing blockade as long as symptoms are likely to occur

 

Pharmacological agents

There are 4 types of antiemetic pharmacological agents.  These include:

• True antiemetics
• Drugs that:
  • potentate antiemetic effects
  • induce sleep
  • decrease anxiety

 

The 3 main classes of drugs used to treat vomiting and nausea in cancer patients are:

Drug	Description
5-HT3 receptor antagonists	Potent antiemetics Came into widespread use in the 1990s in the treatment of cancer patients’ nausea and vomiting
Phenothiazines	Antiemetics used in the therapy of children prior to the advent of 5-HT3 receptor antagonists
Steroids	Modestly effective as antiemetics Used primarily to augment the effects of other antiemetics

 

The following table presents these classes of antiemetics and the symptoms that commonly accompany them:

Table :   The roles of antiemetic drugs in treatment

Class	Drug	Function
5-HT3 receptor antagonists	Ondansetron	Effective when paired with dexamethasone Used in children receiving radiation and chemotherapy
Phenothiazines	Prochlorperazine	Considered safest phenothiazine for children under age 5 Used primarily for its sedative effect
	Perphenazine	Pronounced antiemetic effect
	Thiethylperazine	Not recommended for children under age 2
Steroids	Dexamethasone	Augments effects of other antiemetics Effective in control of delayed vomiting when used in conjunction with metoclopramide