Ppt chapter 59

Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Antiemetic AgentsAntiemetic Agents

Chapter 59


Nausea and VomitingNausea and Vomiting

• Most common and most uncomfortable complaints.

• Vomiting is a complex reflex reaction to various stimuli.

• In some cases, it may be desired to induce vomiting.

• In many clinical conditions, the reflex reaction of vomiting is not beneficial.


Managing Nausea and Vomiting Managing Nausea and Vomiting

• Emetics

– Cause vomiting

– No longer recommended for at-home poison control

• Antiemetics

– Decrease or prevent nausea and vomiting

– Centrally acting or locally acting

– Varying degrees of effectiveness


Sites of Action of Emetics/AntiemeticsSites of Action of Emetics/Antiemetics


Groups of Centrally Acting AntiemeticsGroups of Centrally Acting Antiemetics

• Phenothiazines

• Nonphenothiazines

• Anticholinergics/Antihistamines

• Serotonin (5-HT3) Receptor Blockers

• Substance P/Neurokinin 1 Receptor Antagonists

• Miscellaneous Group


PhenothiazinesPhenothiazines

• Actions

– Depresses various areas of the central nervous system (CNS)

• Indications

– Treatment of nausea and vomiting

• Adverse Effects

– Drowsiness


Nonphenothiazines Nonphenothiazines • Actions

– Acts to reduce the responsiveness of the nerve cells in the CTZ to circulating chemicals that induce vomiting

• Indications

– Prevention of nausea and vomiting

• Adverse Effects

– Drowsiness

– Fatigue

– Restlessness

– Extrapyramidal symptoms


Anticholinergics/AntihistaminesAnticholinergics/Antihistamines• Actions

– Anticholinergics that act as antihistamines and block the transmission of impulses to the CTZ

• Indications

– Prevention and treatment of nausea and vomiting

• Adverse Effects

– Drowsiness

– Confusion

– Dry mouth

– Anorexia

– Urinary frequency


Serotonin (5-HT3) Receptor BlockersSerotonin (5-HT3) Receptor Blockers

• Actions

– Block those receptors associated with nausea and vomiting in the CTZ and locally

• Indications

– Control of nausea and vomiting

• Pharmacokinetics

– Rapidly absorbed, metabolized in the liver, and excreted in urine and feces

• Caution

– Pregnancy and lactation


Serotonin (5-HT3) Receptor Blockers (cont.)

Serotonin (5-HT3) Receptor Blockers (cont.)

• Adverse Effects

– Headache, drowsiness, myalgia, urinary retention, constipation, pain at the injection site


QuestionQuestion

Please answer the following statement as true or false.

Emetic medications are used to induce vomiting and should be kept in the home in case of an accidental poisoning.


AnswerAnswer

False

Rationale: Emetics cause vomiting and are no longer recommended for at-home poison control.


Substance P/Neurokinin 1 Receptor Antagonists

Substance P/Neurokinin 1 Receptor Antagonists

• Actions

– Act directly in the CNS to block receptors associated with nausea and vomiting

• Indications

– In combination with other agents to prevent nausea and vomiting


– Given orally, metabolized in the liver, and excreted in urine and feces


Substance P/Neurokinin 1 Receptor Antagonists (cont.)

Substance P/Neurokinin 1 Receptor Antagonists (cont.)

• Adverse Effects

– Anorexia, fatigue, constipation, diarrhea, liver enzyme elevation, dehydration


Miscellaneous AntiemeticsMiscellaneous Antiemetics

• Actions

– Varies with agent

• Indications

– Treatment and prevention of nausea and vomiting


– Varies according to agent


Miscellaneous Agents (cont.)Miscellaneous Agents (cont.)

• Contraindications

– Coma

– Severe CNS depression

– Brain damage or injury

– Hypotension or hypertension

– Severe liver dysfunction


Miscellaneous Antiemetics (cont.)Miscellaneous Antiemetics (cont.)• Caution

– Renal dysfunction

– Active peptic ulcer disease

– Pregnancy

– Lactation

• Adverse Effects

– Linked to interference with normal CNS stimulation or response

• Drowsiness

• Dizziness

• Weakness


Miscellaneous Antiemetics (cont.)Miscellaneous Antiemetics (cont.)

• Adverse Effects (cont.)

– Photosensitivity

– Hypotension, hypertension, and cardiac arrhythmias

• Drug-to-Drug Interactions

– Alcohol


Use of Drugs Affecting the Female Reproductive System Antiemetic Agents

Across the Lifespan

Use of Drugs Affecting the Female Reproductive System Antiemetic Agents

Across the Lifespan


Prototype PhenothiazinesPrototype Phenothiazines


Prototype Nonphenothiazines Prototype Nonphenothiazines


Prototype Anticholinergics/Antihistamines

Prototype Anticholinergics/Antihistamines


Prototype Serotonin (5-HT3) Receptor Blockers

Prototype Serotonin (5-HT3) Receptor Blockers


Prototype Substance P/Neurokinin 1 Receptor Antagonists

Prototype Substance P/Neurokinin 1 Receptor Antagonists


Nursing Considerations for Antiemetics Nursing Considerations for Antiemetics

• Assessment: History and Physical Exam

• Nursing Diagnosis

• Implementation

• Evaluation


QuestionQuestion

What is an anticholinergic antiemetic recommended for vestibular (inner ear) problems?

A. Granisetron

B. Meclizine

C. Palonosetron

D. Perphenazine


AnswerAnswer

B. Meclizine

Rationale: These drugs—buclizine, cyclizine and meclizine - are anticholinergics that act as antihistamines and block the transmission of impulses to the CTZ. They are recommended for the nausea and vomiting associated with motion sickness or vestibular (inner ear) problems.

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Ppt chapter 59