This presentation was presented to pharmacy students and faculty. The topic of discussion was supportive care in cancer treatment and combating emesis. The presentation looks into the pathophysiology, treatment priniciples and regimes for chemotherapy induced emesis.
2. Objectives
● Discuss the pathophysiology of emesis and types of chemotherapy induced
emesis.
● Discuss the levels of risk and principles of emesis control in chemotherapy.
● Review antiemetic regimes for specified levels of risk.
● Discuss breakthrough emesis and treatment.
3. Pathophysiology of Emesis
● Vomiting results from stimulation of a multistep reflex pathway controlled by the
brain
● Vomiting is triggered by afferent impulses to the vomiting center located in the
medulla from the chemical trigger zone (CTZ), pharynx, GI tract and cerebral
cortex.
● Vomiting occurs when efferent impulses are sent from the vomiting center to the
salivation center, abdominal muscles, respiratory center and cranial nerves
4. Types of Nausea and Vomiting
Chemotherapy-Induced Nausea and/or Vomiting
● Acute: happens within a few minutes or several hours of treatment
● Delayed: occurs more than 24 hours after treatment is given
● Anticipatory: happens before the next treatment is given
● Breakthrough: refers to nausea/vomiting that happens despite trying to prevent it
with drugs
● Refractory: refers to nausea/vomiting that keeps happening even when using drugs
to stop or prevent it
5. Types of Nausea and Vomiting cont.
Radiation induced Nausea and/or Vomiting
● Upper abdomen radiation: Targets the small intestine since it has rapidly dividing
cells. The aim is to kill these rapidly dividing cancer cells
○ Moderate risk for emesis (30-90%)
● Whole Body Radiation: Bone marrow transplant is a cancer treatment that
destroys the soft tissue in the middle of your bones with radiation.
○ >90% risk for emesis
6. Levels of Emesis Risk
● The frequency of anticancer agent- induced emesis depends primarily on the
emetogenic potential of the specific chemotherapeutic agents used.
● Four categories of emetogenic potential for parenteral agents
High Emetic Risk >90% of patients experience acute
emesis
Moderate emetic risk 30-90% of patients experience acute
emesis
Low emetic risk 10-30% of patients experience acute
emesis
Minimal emetic risk <10% of patients experience acute
emesis
7. Principles of Emesis Control
● To provide maximal protection against anticancer agent-induced emesis,
antiemetic therapy should be initiated prior to treatment with anticancer agents
○ Should be continued for the same length of time as the duration of the anticancer agents being
used.
● Prophylactic antiemetic regimes should be chosen based on the drug with the
highest emetic risk, previous experiences with antiemetics, and patient specific
risk factors
● In addition to using antiemetic regimens, patients can adjust their eating habits
and adopt lifestyle measures that may alleviate nausea/vomiting
8. Antiemetic Regimens for Parenteral HEC
● Guidelines recommend three-drug and four-drug antiemetic regimen options for
patients receiving highly emetogenic chemotherapy
● Treatment A
○ Day 1: Olanzapine 5-10 mg, NK1 RA, 5-HT3 RA, Dexamethasone 12 mg PO/IV
○ Day 2-4: Olanzapine 5-10 mg PO, Aprepitant PO on day 2&3 (if used PO on day 1), dexamethasone
8 mg PO/IV
● Treatment B
○ Day 1: Olanzapine 5-10 mg PO once, Palonosetron 0.25 mg IV once, Dexamethasone 12 mg PO/IV
once
○ Day 2-4: Olanzapine 5-10 mg PO
● Treatment C:
○ Day 1: NK1 RA, 5HT3 RA, dexamethasone
○ Day 2-4: Aprepitant PO ( if used as PO on day 1) days 2,3, Dexamethasone 8mg PO/IV on days
2,3,4
9. Antiemetic Regimes for Parenteral MEC
● The guidelines recommend two-drug and three-drug antiemetic regimens for
parenteral moderately emetogenic chemotherapy
● Treatment A
○ Dexamethasone and 5TH3 RA with NK1 RAs such as aprepitant
● Treatment B
○ Olanzapine, Palonosetron and Dexamethasone
● Treatment C
○ Dexamethasone and a 5TH3 RA (Palonosetron or SQ granisetron ER injection are preferred)
10. Antiemetic Regimes for Parenteral Low Emetic Risk
● The single agent antiemetic regimens for low emetogenic risk parenteral
anticancer agents include
○ Dexamethasone, prochlorperazine, metoclopramide, and orally administered 5HT3 RA such as
granisetron, ondansetron, or dolasetron
● When using prochlorperazine or metoclopramide, patients should be monitored
for dystonic reaction
○ Diphenhydramine can be used for the treatment of these reactions or
○ Benztropine in patients who are allergic to diphenhydramine
11. Antiemetic Regimens for Oral Anticancer Agents
For high or moderate
emetic risk oral anticancer
agents
Recommended prophylaxis includes single agent
therapy with granisetron, ondansetron, or
dolasetron
For low or minimal emetic
risk oral anticancer
agents
Recommended oral agents are given on a as
needed basis only and include granisetron,
ondansetron, dolasetron, metoclopramide or
prochlorperazine
12. Breakthrough Nausea and/ or Vomiting Treatment
● Presents a difficult situation since it is much easier to prevent emesis than to treat
it.
● Routine around the clock administration of antiemetics is recommended to
prevent emesis rather than as needed dosing
● The general principle of breakthrough treatment is to add an additional agent as
needed from a different drug class.
● The oral route may not be feasible, consider rectal, topical, SQ or IV therapy
● Another option is to consider changing from current NK-1 containing regime to a
Olanzapine containing regime (or vice versa) prior to the next cycle of anticancer
agents.
13. Radiation Induced Nausea and/ Vomiting
● Antiemetic prophylaxis for radiation induced emesis is based on the site of
therapy and whether it is combined with anticancer agents
● Prophylaxis is dictated by the emetogenic potential of the anticancer regime.
○ Total body irradiation is associated with the highest risk for emesis
○ Upper abdominal RT is associated with moderate risk
● Patients undergoing upper abdominal RT may receive antiemetic prophylaxis with
oral Ondansetron or oral Granisetron with or without Dexamethasone
○ A randomized control study of patients receiving Dexamethasone had better control of emesis.
● Patients Undergoing total body irradiation may receive antiemetic prophylaxis
with oral Ondansetron or oral Granisetron with or without Dexamethasone
14. Resources
● National Comprehensive Cancer Network. Antiemesis (Version 1.2022- January
14, 2022) https://www.nccn.org/professionals/physician_gls/pdf/antiemesis.pdf
