Chapter 59: Antiemetic Agents

When considering the tendency of antiemetic agents to cross the placenta, which assessment question should the nurse initially ask every childbearing aged woman before initiating the therapy?

"Are you pregnant?" Explanation: Assess for possible contraindications or cautions that include the current status of pregnancy and lactation because of the potential for adverse effects on the fetus or nursing baby. None of the other questions addresses the status of the woman regarding a current pregnancy.

A female patient has been administered metoclopramide (Reglan) for nausea. Which statements indicates that she has understood the teaching provided by the nurse?

"I may experience drowsiness with this medication." Explanation: Metoclopramide will produce drowsiness in the patient. The patient should not drink clear liquids with nausea. The patient should not eat with nausea. The patient should not take potassium with metoclopramide.

A nurse is caring for a client admitted to the unit for nausea and vomiting who was treated with ondansetron. A friend visiting the client asks the nurse why the client is sleeping. Which is the nurse's best response?

"The medication makes the client sleepy by blocking the action of the serotonin receptors." Explanation: Ondansetron is a serotonin receptor antagonist and works by antagonizing serotonin receptors, preventing their activation by the emetogenic drugs and toxins. The nurse's best response is telling the friend that the medication blocks the action of the serotonin receptors. It does not block the postganglionic neurons to depress the vomiting center in the brain. Ondansetron does not have anticholinergic effects.

Which statement, made by an older adult who is prescribed an antiemetic, demonstrates effective medication management by the healthcare provider?

"They slowly increased the dose until I stopped vomiting." Explanation: The antiemetic dose for older adults should be started at a lower level than that recommended for young adults and adjusted until the desired results are achieved.

A nurse is preparing to administer hydroxyzine to the nauseated client. Which is included in the teaching plan about the medication?

"This medication will help with the nausea by making you drowsy." Explanation: Hydroxyzine works by blocking the action of acetylcholine in the brain, which relieves the nausea and vomiting and causes the client to feel less nauseated and sleepy. Hydroxyzine does not affect the intestines and does not need to be mixed with applesauce or food.

A client receiving chemotherapy has begun receiving aprepitant. The client also takes oral contraceptives. What should the nurse tell the client in regard to birth control?

"Use alternative means of birth control for 1 month after taking aprepitant." Explanation: A client taking both aprepitant and oral contraceptives must use an alternative form of birth control for at least 1 month after taking aprepitant.

A patient receives prochlorperazine by IM injection. The nurse would expect the drug to begin acting within which time frame?

10 to 20 minutes Explanation: Prochlorperazine, when given by IM injection, has an onset of action of 10 to 20 minutes.

A client is undergoing a course of radiotherapy for the treatment of leukemia. Treatments in the past have caused the client severe nausea and vomiting. The oncology nurse should normally administer antiemetics on what schedule?

30 to 60 minutes before the treatment Explanation: The nurse should normally administer antiemetic drugs 30 to 60 minutes before a nausea-producing event, when possible. None of the other options will provide effective nausea and vomiting relief.

The 5-HT3 receptor blocker, palonosetron, is especially suited for administration to which client?

9:30 AM Explanation: Metoclopramide is given intravenously 30 minutes before chemotherapy.

The 5-HT3 receptor blocker, palonosetron, is especially suited for administration to which client?

A 10 month old experiencing vomiting after chemotherapy Explanation: Palonosetron is approved for use in children 1 month of age and older. None of the other The 5-HT3 receptor blockers have been approved for children under the age of 2 years.

The use of an antiemetic is not clinically safe for which client reporting nausea and vomiting?

A client seen in the emergency room for injuries associated with alcohol intoxication Explanation: Additive CNS depression can be seen with any of the antiemetics if they are combined with other CNS depressants, including alcohol. None of the other client's have an obvious contraindication for this form of medication.

Which nonpharmacologic interventions should the nurse teach the client who is currently reporting nausea and vomiting? Select all that apply.

Acupuncture Acupressure wrist bands Use of herbal supplements Explanation: Nonpharmacologic interventions include acupuncture and acupressure. In a client with nausea and vomiting, eating foods high in sodium and fiber is not indicated. Walking will not decrease the nausea. Use of herbal supplements is also a nonpharmacologic intervention.

Which are locally acting antiemetics? (Select all that apply.)

Antacids Local anesthetics Adsorbents Explanation: Drugs that coat the gastrointestinal tract or prevent distention like antacids, local anesthetics, or absorbents are locally acting antiemetics. Centrally acting medications that act on the chemoreceptor trigger zone or directly suppress vomiting at the medulla are medications such as phenothiazines and non-phenothiazines.

A hospital client has a standing prescription for aprepitant on an as-needed basis. The client should be encouraged to request a dose of the drug in response to which event?

Anticipation of becoming nauseous Explanation: The nurse instructs clients to take aprepitant as prescribed before the onset of nausea and vomiting. It does not need to be taken on a regular schedule and should not be withheld until the onset or peak of symptoms.

Promethazine (Phenergan) is a derivative of phenothiazine making it an antiemetic and also which type of medication?

Antipsychotic Explanation: Specifically, promethazine (Phenergan) inhibits dopaminergic receptors and depresses the release of hormones in the hypothalamus along with other CNS depressant activities, making it an antipsychotic.

The nurse is preparing to administer nabilone to a patient prior to cancer chemotherapy. The nurse understands that this agent is classified as which category of controlled substance?

C-II Explanation: Nabilone is classified as a category C-II controlled substance.

When reviewing a newly admitted client's previous medication record, the nurse notes that the client has previously been treated with aprepitant. The nurse is justified in suspecting that this client's medical history includes which therapy/treatment?

Chemotherapy Explanation: Prescribers often order aprepitant as part of combination therapy along with a 5-HT3 receptor antagonist and corticosteroids to treat both acute and delayed nausea and vomiting associated with chemotherapy. NG tube insertion, radiation therapy, and endoscopy are not typical indications for the use of aprepitant.

A patient develops significant nausea and vomiting related to antineoplastic chemotherapy. Which agent would be most appropriate to use in this situation? (Select all that apply.)

Dolasetron Granisetron Aprepitant Nabilone Explanation: Dolasetron is a 5-HT3 receptor blocker indicated for use with cancer chemotherapy. Granisetron is a 5-HT3 receptor blocker indicated for use with cancer chemotherapy. Aprepitant is a substance P/neurokinin I receptor antagonist indicated for use with cancer chemotherapy. Nabilone is a cannabinoid agent indicated for use with cancer chemotherapy. Hydroxyzine is typically used to treat prepartum, postpartum, and postoperative nausea and vomiting.

A nurse is caring for a pregnant client reporting nausea, which has occurred since the pregnancy began. Which medication does the nurse anticipate the provider to prescribe?

Doxylamine/pyridoxine Explanation: In 2013, the FDA approved Diclegis, a combination of doxylamine succinate, an antihistamine and pyridazine, a form of vitamin B6, for the treatment of nausea and vomiting during pregnancy. Hydroxyzine, cortisol, and meclizine are not approved for use with pregnant clients.

A nurse administers dronabinol to a patient just prior to starting an infusion of chemotherapy drugs. Before allowing the patient to leave the facility, what should the nurse instruct the patient to avoid?

Driving Explanation: Dronabinol, which may be administered prior to chemotherapy drugs to control nausea and vomiting, can cause dizziness, drowsiness, mood changes, and other mind-altering effects. Patients receiving dronabinol should not drive or perform hazardous tasks requiring alertness, coordination, or physical dexterity, to decrease risks of injury. Additionally, patients should avoid alcohol and other drugs that cause drowsiness.

A female client is receiving chemotherapy to treat her cancer. Several antiemetics have been prescribed, and each has been unsuccessful in treating her nausea and vomiting. The health care provider chooses to prescribe what cannabinoid drug to manage her symptoms?

Dronabinol Explanation: Dronabinol is a cannabinoid used in the management of nausea and vomiting associated with chemotherapy unrelieved by other antiemetic drugs. It is a Schedule III drug under federal narcotic laws.

The nurse is providing education to a client who has been prescribed hydroxyzine. What adverse effect should the nurse mention during teaching?

Drowsiness Explanation: The use of hydroxyzine is associated with drowsiness. Antihistamines do not typically cause pruritus, frequency, or bradycardia.

The nurse administers hydroxyzine to a client with nausea. After administration, the nurse should monitor for what adverse effect?

Dry mouth Explanation: Anticholinergic effects, including dry mouth, can result from the use of hydroxyzine. This drug is not associated with thrombocytopenia, palpitations, or hypertonicity.

A child is administered metoclopramide (Reglan) for nausea. What adverse effect is likely with this medication?

Dystonia Explanation: Metoclopramide given to children produces dystonia. Metoclopramide does not cause thrombocytopenia, palpitations, or malignant hyperthermia.

Which practice reported by a parent requires immediate attention by the nurse?

Encouraging their child to take prescribed medication by referring to it as candy Explanation: Never refer to medications as candy or a treat. The remaining options are all accurate practices.

The nurse is caring for a 19-month-old child who has been hospitalized with dehydration secondary to nausea and vomiting. The nurse is aware that promethazine will not be used for this client because it can cause what in children under the age of 2?

Fatal respiratory depression Explanation: A black box warning alerts nurses that promethazine is contraindicated in children younger than 2 years of age because of the risk of potentially fatal respiratory depression. When using promethazine, the lowest effective dosage should be used, and other drugs with respiratory depressant effects should not be given concurrently. Excessive doses may cause hallucinations, convulsions, and sudden death.

The nurse is caring for a client who has just had an episode of vomiting. What is the first intervention that the nurse would complete after the client has finished vomiting?

Help the client rinse his mouth. Explanation: The nurse should immediately help the client rinse out his mouth which helps take away the taste and sensation of vomit.

The nurse should explain that metoclopramide (Reglan) decreases nausea and vomiting by which of the following actions?

Inhibiting stimulation of the vomiting center in the brain Explanation: Reglan inhibits stimulation of the vomiting center in the brain. This medication also increases the amplitude of gastric contractions and gastric motility while decreasing gastric emptying time.

Which would be most important for the nurse to do when administering a phenothiazine antiemetic to a patient?

Institute safety precautions Explanation: Adverse effects associated with phenothiazines are linked to their interference with normal CNS stimulation. The patient's risk for injury is high. Withholding food and fluids would not be necessary unless the patient's vomiting was not controlled and food or fluid intake exacerbated his vomiting. Respiratory adverse effects are not associated with the use of phenothiazines. Although urinary retention may occur, catheterization would be a last resort.

The nurse is preparing medications for a client experiencing nausea. Which action will the nurse take when preparing a dose of ondansetron for this client?

Leave the tablet in the blister pack until just before administration. Explanation: Oral ondansetron is well absorbed from the gastrointestinal tract to treat nausea. It is important to leave the disintegrating tablet in the blister pack until administration. The tablet is not crushed before administering because it rapidly dissolves on the tongue. Gentle removal of the tablet from the blister pack is needed; rather than push the pill through the foil backing, the nurse should peel the foil away. Fluids are not required for this medication as it will dissolve on the tongue.

Which part of the brain is responsible for autonomic functioning such as ventilation, cardiac conduction, and vomiting?

Medulla oblongata Explanation: The medulla oblongata is the vomiting center as well as the center for other autonomic functioning. It is located in the hindbrain. The pineal gland and the pituitary gland are glands located in the forebrain and are responsible for endocrine functioning. The hypothalamus is a part of the limbic system.

Vomiting occurs when signals from the chemoreceptor trigger zone reach the vomiting center. Where is the vomiting center located?

Medulla oblongata Explanation: The vomiting center is a nucleus of cells in the medulla oblongata.

Prokinetic agents increase GI motility and the rate of gastric emptying, which can decrease nausea and vomiting in nonobstructive disorders. Which prokinetic agent would the nurse expect the physician to prescribe?

Metoclopramide Explanation: Metoclopramide is a prokinetic agent that increases GI motility and the rate of gastric emptying by increasing the release of acetylcholine from nerve endings in the GI tract (peripheral cholinergic effects).

A hospitalized toddler has been prescribed an antiemetic. The nurse will implement which intervention based on the child's unique needs?

Monitoring for electrolyte imbalances Explanation: Antiemetics should be used with caution in children who are at higher risk for adverse effects, including CNS effects, as well as fluid and electrolyte disturbances. The older adult is at risk for liver related issues when prescribed an antiemetic. Both of the remaining options would be appropriate for any hospitalized child.

What information should the nurse include in a discussion on accidental poisoning when working with a group of new parents? Select all that apply.

Never refer to medications as candy or a treat. Always return any childproof caps to the locked position after they are used. Never transfer a potentially poisonous substance from its original container. If a local poison control center is not available, call 1-800-222-1222. Explanation: The new guidelines set forth by the American Academy of Pediatrics (AAP) for anticipatory counseling for prenatal and well-infant visits include: • Keep potential poisons out of sight and out of reach. • Always return any childproof caps to the locked position after they are used. • Never transfer a substance to a different container; it is important to have the information on the original container in case of emergency. • Safely dispose of all unused or no-longer-needed medication. • Never refer to medications as candy or a treat. • Post the telephone number of the poison control center near the phone. If a local poison control center is not available, post 1-800-222-1222.

What antiemetic is the most common first-line drug for the treatment of postoperative nausea and vomiting?

Ondansetron Explanation: The 5-HT3 receptor antagonists are usually considered drugs of first choice for postoperative nausea and vomiting. Ondansetron is the prototype of the 5-HT3 receptor antagonists. None of the remaining options are a 5-HT3 receptor antagonist.

Which would an instructor include as an example of a phenothiazine used as an antiemetic?

Perphenazine Explanation: Perphenazine is a phenothiazine antiemetic. Granisetron is classified as a 5-HT3 receptor blocker. Cyclizine is an anticholinergic/antihistamine antiemetic. Metoclopramide is a nonphenothiazine antiemetic.

A client has been prescribed a phenothiazine for chemotherapy related nausea and vomiting. Which urinary side effect should the nurse include when educating the client on this medication?

Pink to red brown urine Explanation: Patients taking a phenothiazine should be cautioned that their urine may be tinged pink to red-brown. This is a drug effect but can cause concern if the patient is not expecting it. None of the other options are associated with this classification of medication.

A client has been told that stimulation of their chemoreceptor trigger zone (CTZ) is responsible for their current symptoms. What nursing action indicates that the nurse is aware of the role of the CTZ?

Planning care to manage the client's nausea and vomiting Explanation: The CTZ, located in the brain is referred to as the vomiting center. Nausea and vomiting are experienced when this center is stimulated. The remaining options are associated with adverse reactions to antiemetic medications.

A client prescribed promethazine has an elevated creatinine level. Which action is the health care provider likely to take considering any possible related risk to this client?

Prescribe administration of a lower dose Explanation: A dose reduction may be necessary in clients with renal impairment to avoid the possibility of adverse effects, toxicity, or increased sensitivity to phenothiazines. A change in frequency is less likely.

A 1-year-old postoperative client has been experiencing repeated vomiting. What antiemetic drug has a black box warning against use in a client of this age?

Promethazine Explanation: A black box warning alerts nurses that promethazine is contraindicated in children younger than 2 years of age because of the risk of potentially fatal respiratory depression. Benzquinamide, buclizine, and cyclizine do not have such warnings.

Why is buclizine an effective antiemetic?

Promotes anticholinergic effects Explanation: These drugs are anticholinergics that act as antihistamines and block the transmission of impulses to the CTZ.

Ondansetron (Zofran) belongs to which pharmacological category of medications?

Selective 5-HT3 receptor antagonist Explanation: Ondansetron (Zofran) is a selective 5-HT3 receptor antagonist.

Several neurotransmitters have been identified with nausea and vomiting. In this capacity, they act as neuromediators. What neuromediator is thought to be involved in the nausea and vomiting that accompanies chemotherapy?

Serotonin Explanation: The 5-HT3 (serotonin) receptor blockers have proven especially helpful in treating the nausea and vomiting associated with antineoplastic chemotherapy, radiation therapy, and postoperative nausea and vomiting. Serotonin is believed to be involved in the nausea and emesis associated with cancer chemotherapy and radiation therapy. Serotonin antagonists (e.g., granisetron and ondansetron) are effective in treating the nausea and vomiting associated with these stimuli. The other answers are incorrect.

Aprepitant (Emend) is the prototype of which class of antiemetic medications?

Substance P/neurokinin 1 antagonist Explanation: Aprepitant (Emend) is a prototype of the class substance P/neurokinin 1 antagonists.

The nurse is discussing the possible side effects of chemotherapy with a client. What information obtained during the client's admission assessment and interview will have a direct influence on the management of nausea and vomiting

The client has been prescribed phenothiazine for anxiety Explanation: Phenothiazine is antianxiety drug that blocks the responsiveness of the CTZ to stimuli, leading to a decrease in nausea and vomiting. None of the other options are related to chemotherapy induced nausea and vomiting.

Which intervention has priority when caring for an older adult client who has been prescribed a phenothiazine for reported nausea?

The client is identified as a possible falls risk Explanation: Older adults are more likely to develop adverse effects associated with the use of these drugs. Safety measures may be needed if these effects occur and interfere with the patient's mobility and balance increasing their risk for falls. While the other options present possible side effects, none have the priority of falls management.

In which of the following scenarios would the nurse question the order for ondansetron (Zofran)?

Treatment of gastresophageal reflux Explanation: Because the mechanism of action of ondansetron (Zofran) does not act directly on the gastrointestinal system as other antiemetics do, the nurse should question this order as a treatment for gastresophageal reflux.

The nurse is working in the medical station at a local amusement park. An adult is reporting dizziness and feelings of "seasickness" after going on several rides. This patient may benefit from:

an anticholinergic. Explanation: The nausea and vomiting associated with motion sickness is best treated with an anticholinergic that acts as an antihistamine. Histamine H2 blockers affect gastric acid production. Substance p/neurokinin 1 receptor antagonist and cannabis are strictly prescribed as adjuncts to cancer chemotherapy drugs or therapy.

A nurse is preparing to administer dolasetron orally to a child who is unable to swallow the tablet. The nurse would expect to mix the solution with:

apple juice. Explanation: Dolasetron solution can be mixed with apple or apple-grape juice for administration.

A client has been prescribed promethazine for recurrent nausea. The nurse should anticipate what preferred route for administration?

intramuscular injection Explanation: The preferred parenteral route of administration is intramuscular, which reduces risk of surrounding muscle and tissue damage. The FDA has issued a black box warning alerting nurses that promethazine is contraindicated for subcutaneous administration. Intravenous administration should be avoided, if possible, because the drug can cause severe tissue injury. Topical application is not an option.

A client reports taking antihistamines to treat nausea. The nurse correctly suspects that the nausea results from what trigger?

motion sickness. Explanation: Antihistamines are usually effective in preventing or treating nausea and vomiting induced by motion sickness. They are not prescribed for nausea triggered by drugs, surgery, or radiation therapy.

What are the most common adverse effects associated with drug therapy?

nausea and vomiting Explanation: Nausea and vomiting are the most common adverse effects of drug therapy. While the other options are possible, they are not as common as is nausea and vomiting.

Postoperative nausea and vomiting may be managed with what serotonin receptor antagonists? Select all that apply.

ondansetron dolasetron granisetron Explanation: Ondansetron, granisetron, dolasetron, and palonosetron are used to prevent or treat moderate to severe nausea and vomiting associated with cancer chemotherapy, radiation therapy, and postoperative status. Rizatriptan and promethazine are serotonin receptor antagonists used to treat migraines.