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Questions and Answers
Which neurotransmitter is NOT primarily involved in the vomiting pathway as described?
Which neurotransmitter is NOT primarily involved in the vomiting pathway as described?
What is the primary action of H1 receptor antagonists in relation to vomiting?
What is the primary action of H1 receptor antagonists in relation to vomiting?
Which type of receptors are implicated in the effects of motion sickness?
Which type of receptors are implicated in the effects of motion sickness?
Which condition is least likely to cause vomiting as described?
Which condition is least likely to cause vomiting as described?
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Which of the following drugs would likely be classified as a 5-HT3 receptor antagonist?
Which of the following drugs would likely be classified as a 5-HT3 receptor antagonist?
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What adverse effect is most commonly associated with first-generation antihistamines?
What adverse effect is most commonly associated with first-generation antihistamines?
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Which of the following actions is true regarding enkephalins in the context of vomiting?
Which of the following actions is true regarding enkephalins in the context of vomiting?
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Which of the following stimuli is most likely to trigger nausea in patients?
Which of the following stimuli is most likely to trigger nausea in patients?
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What is the first line treatment for nausea and vomiting in pregnancy?
What is the first line treatment for nausea and vomiting in pregnancy?
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Which medication is used as a second-line treatment for nausea and vomiting when anti-H1 options fail?
Which medication is used as a second-line treatment for nausea and vomiting when anti-H1 options fail?
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Which of the following is NOT a common symptom of Ménière's disease?
Which of the following is NOT a common symptom of Ménière's disease?
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Which medication is characterized as an H3 receptor antagonist and a partial H1 agonist for the prevention of Ménière's attacks?
Which medication is characterized as an H3 receptor antagonist and a partial H1 agonist for the prevention of Ménière's attacks?
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What is the role of dexamethasone in treating Ménière's disease?
What is the role of dexamethasone in treating Ménière's disease?
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Which antipsychotic medication also serves for severe nausea and vomiting as indicated in treatments for Ménière's disease?
Which antipsychotic medication also serves for severe nausea and vomiting as indicated in treatments for Ménière's disease?
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What are the potential adverse effects of scopolamine, particularly in the context of motion sickness treatment?
What are the potential adverse effects of scopolamine, particularly in the context of motion sickness treatment?
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If symptoms of nausea do not resolve with first-line treatments, which of the following should be considered?
If symptoms of nausea do not resolve with first-line treatments, which of the following should be considered?
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What is the primary mechanism of action for 5-HT3 receptor antagonists in reducing nausea and vomiting?
What is the primary mechanism of action for 5-HT3 receptor antagonists in reducing nausea and vomiting?
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In which situation is ondansetron typically indicated for use?
In which situation is ondansetron typically indicated for use?
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What adverse effect is notably associated with metoclopramide due to its D2 antagonist properties?
What adverse effect is notably associated with metoclopramide due to its D2 antagonist properties?
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What distinguishes domperidone from other dopamine antagonists in its clinical use?
What distinguishes domperidone from other dopamine antagonists in its clinical use?
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For which condition are antipsychotic drugs primarily used as antiemetics?
For which condition are antipsychotic drugs primarily used as antiemetics?
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Which of the following statements is true regarding NK1 receptor antagonists?
Which of the following statements is true regarding NK1 receptor antagonists?
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What serious risk is associated with the use of domperidone, particularly at higher doses?
What serious risk is associated with the use of domperidone, particularly at higher doses?
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Which of the following is a common side effect of chlorpromazine used as an antiemetic?
Which of the following is a common side effect of chlorpromazine used as an antiemetic?
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What is the primary mechanism of action of dopamine antagonists like metoclopramide?
What is the primary mechanism of action of dopamine antagonists like metoclopramide?
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Which condition is specifically treated with domperidone due to its unique properties?
Which condition is specifically treated with domperidone due to its unique properties?
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What adverse effect is associated with the use of first-generation antipsychotics for antiemetic purposes?
What adverse effect is associated with the use of first-generation antipsychotics for antiemetic purposes?
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What is a significant side effect associated with the use of NK1 receptor antagonists?
What is a significant side effect associated with the use of NK1 receptor antagonists?
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Which receptor is primarily targeted by 5-HT3 receptor antagonists to mitigate nausea and vomiting?
Which receptor is primarily targeted by 5-HT3 receptor antagonists to mitigate nausea and vomiting?
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What is the preferred method of administration for dopamine antagonists when treating severe nausea and vomiting?
What is the preferred method of administration for dopamine antagonists when treating severe nausea and vomiting?
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What general class of drugs does palonosetron belong to for managing nausea and vomiting?
What general class of drugs does palonosetron belong to for managing nausea and vomiting?
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What is a notable central nervous system side effect of metoclopramide?
What is a notable central nervous system side effect of metoclopramide?
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What role do afferent pathways play in the vomiting process?
What role do afferent pathways play in the vomiting process?
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Which of the following neurotransmitters is NOT primarily associated with the vomiting pathway?
Which of the following neurotransmitters is NOT primarily associated with the vomiting pathway?
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What is a common adverse reaction of first-generation antihistamines used as antiemetics?
What is a common adverse reaction of first-generation antihistamines used as antiemetics?
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Which condition is most likely to be treated with 5-HT3 receptor antagonists?
Which condition is most likely to be treated with 5-HT3 receptor antagonists?
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What is the primary function of NK1 receptor antagonists in antiemetic treatment?
What is the primary function of NK1 receptor antagonists in antiemetic treatment?
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Which receptor types are primarily targeted by antiemetic medications for treating motion sickness?
Which receptor types are primarily targeted by antiemetic medications for treating motion sickness?
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What is the hypothesized role of enkephalins in the context of vomiting?
What is the hypothesized role of enkephalins in the context of vomiting?
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What is the main mechanism of action for antihistamines in treating nausea and vomiting?
What is the main mechanism of action for antihistamines in treating nausea and vomiting?
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What is the recommended dosage range for pyridoxine as a first-line treatment for nausea and vomiting during pregnancy?
What is the recommended dosage range for pyridoxine as a first-line treatment for nausea and vomiting during pregnancy?
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Which of the following medications is used for acute attacks in Ménière's disease?
Which of the following medications is used for acute attacks in Ménière's disease?
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Which medication can be considered for unresolved nausea and vomiting after trying anti-H1 options?
Which medication can be considered for unresolved nausea and vomiting after trying anti-H1 options?
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What characteristic of betahistine makes it effective for preventing Ménière's attacks?
What characteristic of betahistine makes it effective for preventing Ménière's attacks?
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What is a potential adverse effect of using scopolamine for motion sickness?
What is a potential adverse effect of using scopolamine for motion sickness?
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Which route of administration is likely to have fewer adverse effects for scopolamine?
Which route of administration is likely to have fewer adverse effects for scopolamine?
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What distinguishes prochlorperazine as a treatment in the context of severe nausea?
What distinguishes prochlorperazine as a treatment in the context of severe nausea?
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Study Notes
Lesson 20: Vomiting
- This lesson covers vomiting, its pathophysiology, and antiemetic drugs.
- The academic year is 2024/25.
- The professor is Vittoria Carrabs PhD.
1. Pathophysiology of Vomiting
- Vomiting is a complex process involving multiple steps.
- Stimuli initiate the process, which travels through sensory pathways to the medulla.
- The medulla contains the vomit center, integrating signals and coordinating emesis.
- The vomit center then stimulates the gastrointestinal tract and diaphragm, resulting in vomiting.
- Factors involved include unpleasant images/odors/emotions, irritative stimuli (chemo, radiotherapy, gastroenteritis); motion sickness, vertigo, toxins, drugs.
- The labyrinth, vestibular nuclei, and chemoreceptor trigger zone (CTZ) play vital roles in this process, with the CTZ receiving input from the blood regarding emetogens and integrating stimuli.
- Neurotransmitters involved include acetylcholine, histamine, dopamine, substance P, and Enkephalins.
2. Antiemetic Drugs
- These are drugs used to treat nausea and vomiting.
2.1 Antihistamines (H1 receptor antagonists)
- These drugs effectively treat nausea and vomiting arising from various causes, including motion sickness and stomach irritants.
- Examples include promethazine, dimenhydrinate, betahistine, and doxylamine.
- The mechanism of action involves blocking H1 receptors in the vestibular nuclei and gastrointestinal tract.
- Side effects can include drowsiness and sedation.
- Specific examples include Biodramina 50mg (Dimenhydrinate), Promethazine, Doxylamine (12.5-25 mg every 8 hours). Pyridoxine (vitamin B6) 10-25 mg every 8 hours is a first-line treatment for nausea and vomiting in pregnancy.
2.2 Muscarinic Receptor Antagonists
- Scopolamine (Hyoscine) is used for motion sickness prophylaxis and treatment.
- It is administered orally or intramuscularly, typically for short periods of intense motion.
- Transdermal administration is also a method, showing fewer side effects.
- Side effects include mydriasis, tachycardia, and urinary retention.
2.3 5-HT3 Receptor Antagonists
- Granisetron, ondansetron, and palonosetron are examples of 5-HT3 receptor antagonists.
- These drugs are effective in preventing nausea and vomiting associated with cancer chemotherapy.
- They can also be used to prevent post-operative nausea and vomiting. Dosage can be oral or intravenous (IV) depending on the severity and type of chemotherapy.
2.4 Dopamine Antagonists
- Metoclopramide and Domperidone are examples.
- Metoclopramide is used to prevent and treat nausea and vomiting associated with migraine, gastroesophageal reflux, hepatic/biliary disorders. Metoclopramide has an additional effect of increasing gastrointestinal motility.
- Domperidone does not cross the blood-brain barrier (BBB).
- Useful in treating nausea and vomiting induced by levodopa, cytotoxic treatments, particularly useful in the delayed phase of chemotherapy induced emesis.
2.5 NK1 Receptor Antagonists
- Aprepitant and fosaprepitant are examples of NK1 receptor antagonists.
- Useful in treating the delayed phase of nausea and vomiting induced by chemotherapy, after cytotoxic treatments.
2.6 Other Antiemetics
- Nabilone, a synthetic cannabinoid, can reduce vomiting caused by CTZ-stimulating agents. It can be more effective than other antiemetics.
- High-dose Glucocorticoids (particularly dexamethasone) work in combination with other antiemetics.
2.7 Antiemetics for specific conditions
- Meniere's Disease: Prochlorperazine, buccal or intramuscular, and short-term benzodiazepines may be used to treat acute attacks. Betahistine (H3 receptor antagonist) and dexamethasone (immunomodulator) are also used in cases of suspected autoimmune origin
- Antihistamines are also recommended, as a part of a multi-component treatment strategy.
- Antipsychotics (Chlorpromazine, Prochlorperazine, Perphenazine): Effective treatment for severe cases where the above methods fail. Limited use to severe cases due to significant side effects. These drugs are administered orally, IV, or rectally. Side effects include sedations, hypotension, and extrapyramidal symptoms, including dystonias and tardive dyskinesias.
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Description
This quiz covers the complex process of vomiting, including its pathophysiology and the role of antiemetic drugs. Understand how stimuli affect the medulla's vomit center and learn about the various factors that can lead to emesis. Prepare to explore neurotransmitters involved in this crucial physiological response.
