Chapter 52: Antiemetic & Antinausea Drugs

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What should be monitored closely in patients receiving antiemetics?

Only for therapeutic effects

Both therapeutic and adverse effects (correct)

Only for adverse effects

For drowsiness only

What is a nursing implication when treating nausea and vomiting?

Ignore allergies when assessing patients

Avoid reviewing the patient's medication history

Carefully review current medications for interactions (correct)

Educate patients only about side effects

How should patients be advised regarding the use of ginger?

It should only be taken in large doses

It reduces the absorption of all medications

It has no interaction with any medications

It may increase bleeding risk with anticoagulants (correct)

What is an important patient education topic regarding antiemetic medications?

Patients should avoid alcohol due to potential interactions Signup and view all the answers

What is the recommended timing for administering antiemetics before chemotherapy?

30-60 minutes before chemotherapy Signup and view all the answers

What is the role of antiemetic drugs?

To prevent nausea and vomiting Signup and view all the answers

Where is the Vomiting Center (VC) located?

In the medulla oblongata Signup and view all the answers

What triggers the Chemoreceptor Trigger Zone (CTZ)?

Noxious stimuli detected in the blood Signup and view all the answers

How do anticholinergic drugs work to prevent nausea?

By binding to and blocking acetylcholine receptors Signup and view all the answers

What is Scopolamine primarily used to treat?

Postoperative nausea and motion sickness Signup and view all the answers

What effect do antiemetics have on vomiting symptoms?

They reduce the severity of symptoms Signup and view all the answers

Which of the following is a common pathway triggering vomiting?

Toxin detection in the blood Signup and view all the answers

What is one of the main mechanisms of action for antiemetics?

Blocking neurotransmitters Signup and view all the answers

What is the primary mechanism of action of serotonin blockers in treating nausea?

Blocking serotonin receptors in the gastrointestinal tract Signup and view all the answers

Which drug is an example of a tetrahydrocannabinoid used to manage chemotherapy-induced nausea?

Dronabinol Signup and view all the answers

What effect do tetrahydrocannabinoids have on the body related to nausea and vomiting?

They alter mood and perception to alleviate sensations Signup and view all the answers

Which adverse effect is commonly associated with many antiemetics?

Dry mouth and constipation Signup and view all the answers

For which condition is phosphorated carbohydrate solution, like Emetrol, used off-label?

Morning sickness Signup and view all the answers

What is a significant consideration when using tetrahydrocannabinoids for nausea treatment?

They require careful monitoring Signup and view all the answers

Which of the following represents a common side effect of antiemetic drugs?

Drowsiness Signup and view all the answers

What property of ginger makes it a popular natural remedy for nausea?

It is effective in treating gastrointestinal upset Signup and view all the answers

What is the primary mechanism of action of antihistamines?

Block H1 receptors and inhibit acetylcholine Signup and view all the answers

Which of the following is a common indication for the use of antihistamines?

Alleviation of motion sickness Signup and view all the answers

What potential complication is associated with long-term use of prokinetic drugs?

Tardive dyskinesia Signup and view all the answers

Which drug is classified as an antidopaminergic medication?

Promethazine Signup and view all the answers

What is a key precaution when administering hydroxyzine?

Ensure it is given orally or intramuscularly Signup and view all the answers

Which neurokinin receptor antagonist is a water-soluble prodrug?

Fosaprepitant Signup and view all the answers

What is the main therapeutic use of prokinetic drugs?

Enhance gastrointestinal motility Signup and view all the answers

Which of the following is a potential use for antidopaminergic drugs?

Control of nausea and vomiting Signup and view all the answers

Study Notes

Serotonin Blockers

Block serotonin receptors in the gastrointestinal (GI) tract, chemoreceptor trigger zone (CTZ), and vomiting center (VC)
Used for nausea and vomiting in chemotherapy and post-operative patients
Examples: Dolasetron (Anzemet), Granisetron (Kytril), Ondansetron (Zofran), Palonosetron (Aloxi)

Tetrahydrocannabinoids

Primary psychoactive component in marijuana
Exert inhibitory effects on the brain's reticular formation, thalamus, and cerebral cortex
Clinically used to manage chemotherapy-induced nausea and vomiting, and anorexia in HIV/AIDS patients
Example: Dronabinol (Marinol)

Phosphorated Carbohydrate Solution

Emetrol is a mint-flavored oral solution, used off-label for morning sickness
Mint flavor may improve palatability and patient compliance
Effective for nausea and vomiting and considered relatively safe

Adverse Effects of Antiemetics

Drowsiness
Dry mouth
Blurred vision (antihistamines)
Constipation

Ginger for Nausea

Natural remedy used to treat nausea and vomiting
Conditions treated include chemotherapy-induced nausea, morning sickness, and motion sickness
Possible side effects: mild gastrointestinal upset, skin reactions
May increase the absorption of oral medications and bleeding risk with anticoagulants

Nursing Implications

Thoroughly assess the patient's history of nausea and vomiting and note precipitating factors
Carefully review the patient's current medications and identify potential drug interactions
Check for contraindications and assess for allergies
Warn patients about drowsiness and advise against operating machinery
Educate patients on potential drug interactions, such as with alcohol
Emphasize slow position changes to prevent hypotension
Closely monitor patients for both therapeutic and adverse effects, including nausea, vomiting, and other symptoms
Administer antiemetics 30-60 minutes before chemotherapy

Definitions: Nausea and Vomiting

Nausea: Unpleasant sensation that often precedes vomiting
Emesis (Vomiting): Forcible emptying of gastric contents, occasionally intestinal contents as well
Antiemetic drugs: Used to treat nausea and vomiting, effectively relieving symptoms

Vomiting Center and Chemoreceptor Trigger Zone

Vomiting Center (VC): Located in the medulla oblongata, receives signals from various sources and initiates the vomiting reflex when stimulated
Chemoreceptor Trigger Zone (CTZ): Near the VC, but outside the blood-brain barrier, detects toxins in the blood and coordinates with the VC to initiate emetic responses

Antiemetics and Antinausea Drugs: Mechanism of Action

Vomiting Pathways: Multiple pathways trigger vomiting, antiemetics block these
Neurotransmitter Blockade: Many drugs block neurotransmitters to prevent the vomiting signals
Receptor Interactions: Drugs bind to receptors to inhibit vomiting signals

Anticholinergic Drugs

Block acetylcholine (ACh) receptors, preventing transmission of nausea-inducing stimuli to the CTZ
Interrupt signals from the reticular formation to the vomiting center
Example: Scopolamine (Transderm-Scōp, Scopace) - available as a 72-hour transdermal patch, effective in preventing motion sickness and postoperative nausea

Antihistamine Drugs

Inhibit ACh by binding to H1 receptors, preventing cholinergic stimulation
Effective in treating motion sickness, nonproductive coughs, and allergy symptoms
Some provide sedation
Examples: dimenhydrinate (Dramamine), diphenhydramine (Benadryl), meclizine (Antivert), hydroxyzine (Vistaril)

Antidopaminergic Drugs

Block dopamine receptors in the CTZ to reduce nausea and vomiting
Other indications: psychotic disorders, intractable hiccups
Examples: Prochlorperazine (Compazine), promethazine (Phenergan), amisulpride (Barhemsys), droperidol
Preferred administration routes: oral and intramuscular, IV route is common but not preferred
Droperidol use is controversial due to cardiac risks

Neurokinin Receptor Antagonists

Inhibit substance P/neurokinin 1 receptors, reducing chemotherapy-induced nausea
Examples: Aprepitant, Fosaprepitant (water-soluble prodrug of aprepitant), Rolapitant

Prokinetic Drugs

Block dopamine receptors in the CTZ, desensitizing the CTZ to GI tract impulses
Stimulate GI tract peristalsis, enhancing stomach emptying
Other indications: gastroesophageal reflux disease, delayed gastric emptying
Example: Metoclopramide (Reglan) - long-term use may cause tardive dyskinesia

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers various antiemetics, including serotonin blockers, tetrahydrocannabinoids, and phosphorated carbohydrate solutions. You will also explore the adverse effects associated with these medications and the use of ginger for nausea management. Test your knowledge of these important pharmacological agents in treating nausea and vomiting.