Antiemetic and Antinausea Drugs PDF

Antiemetic and Antinausea Drugs Chapter 52: Understanding Antiemetics These drugs help prevent nausea and vomiting. They're crucial in various medical settings. KR by Katie Robinson Definitions: Nausea and Vomiting Nausea Emesis (Vomiting) Antie...

Antiemetic and Antinausea Drugs Chapter 52: Understanding Antiemetics These drugs help prevent nausea and vomiting. They're crucial in various medical settings. KR by Katie Robinson Definitions: Nausea and Vomiting Nausea Emesis (Vomiting) Antiemetic Drugs An unpleasant sensation. Often Forcible emptying of gastric Used to treat nausea and precedes vomiting. contents. Occasionally, intestinal vomiting. Relieve symptoms contents as well. effectively. Vomiting Center and Chemoreceptor Trigger Zone Vomiting Center (VC) Chemoreceptor Trigger Zone (CTZ) Located in the medulla oblongata. Receives signals Near the VC, but outside from various sources. the blood-brain barrier. Detects toxins in the blood. Stimulation and Reflex Complex Interaction When stimulated, both The VC and CTZ interact to areas initiate the vomiting coordinate emetic reflex. responses. Antiemetics and Antinausea Drugs: Mechanism of Vomiting Pathways Neurotransmitter Blockade Receptor Interactions Multiple pathways trigger vomiting. Many drugs block neurotransmitters. Drugs bind to receptors. This stops Antiemetics block these. This prevents vomiting. the vomiting signals. Indications Prevention Antiemetics prevent nausea and vomiting. Reduction They reduce the severity of symptoms. Varied Use Specific uses depend on the drug class. Antiemetics are used to treat various conditions causing nausea and vomiting. These include surgery, chemotherapy, and motion sickness. Specific indications vary widely. Anticholinergic Drugs: Mechanism of Action and Indications Mechanism of Action Example: Scopolamine Anticholinergic drugs, also known as acetylcholine (ACh) Scopolamine (Transderm-Scōp, Scopace) is a common blockers, work by binding to and blocking ACh receptors. anticholinergic drug. This action prevents transmission of nausea-inducing It's available as a 72-hour transdermal patch. stimuli to the chemoreceptor trigger zone (CTZ). Each patch releases 1 mg of scopolamine. They also interrupt signals from the reticular formation to It's effective in preventing motion sickness and the vomiting center (VC). postoperative nausea. Antihistamine Drugs: Mechanism of Action and Indications Mechanism of Action Indications Antihistamines, or H1 receptor These drugs effectively treat blockers, inhibit acetylcholine motion sickness. They also (ACh) by binding to H1 alleviate nonproductive coughs receptors. This action prevents and allergy symptoms. Some cholinergic stimulation, also provide sedation. reducing nausea and vomiting. Examples Important Note Common antihistamines include Hydroxyzine (Vistaril) is dimenhydrinate (Dramamine), administered orally or diphenhydramine (Benadryl), intramuscularly; never meclizine (Antivert), and intravenously. hydroxyzine (Vistaril). Antidopaminergic Drugs: Mechanism of Action and Indications Mechanism of Action Other Indications Antidopaminergic drugs block These drugs are also used to treat dopamine receptors in the psychotic disorders. chemoreceptor trigger zone (CTZ). They may also be used for This action helps reduce nausea and intractable hiccups. vomiting. Examples Administration and Cautions Prochlorperazine (Compazine), Oral and IM routes are preferred for promethazine (Phenergan). promethazine. Amisulpride (Barhemsys), Droperidol IV route is common but not are other examples. preferred; never intraarterial. Droperidol use is controversial due to cardiac risks. Neurokinin Receptor Antagonists: Mechanism of Action and Indications Aprepitant Fosaprepitant Rolapitant Inhibits substance P/neurokinin 1 Water-soluble prodrug of aprepitant. Another neurokinin-1 receptor receptors. Reduces chemotherapy- Rapid absorption, convenient for IV antagonist. Effective in preventing induced nausea. administration. CINV. Prokinetic Drugs: Mechanism of Action and Indicat Mechanism of Action Other Indications Prokinetic drugs block dopamine receptors in the Prokinetic drugs are used to treat gastroesophageal reflux chemoreceptor trigger zone (CTZ). disease. This desensitizes the CTZ to GI tract impulses. They're also used for delayed gastric emptying. They also stimulate GI tract peristalsis. Metoclopramide (Reglan) is a common example. This enhances the emptying of stomach contents. Long-term use may cause tardive dyskinesia. Serotonin Blockers: Mechanism of Action and Indic Mechanism of Action Indications Examples Block serotonin receptors in the GI Used for nausea and vomiting in Dolasetron (Anzemet), Granisetron tract, chemoreceptor trigger zone chemotherapy and post-operative (Kytril), Ondansetron (Zofran), (CTZ), and vomiting center (VC). patients. Palonosetron (Aloxi). Tetrahydrocannabinoids: Mechanism of Action and Indi Mechanism of Action Effects on Perception Clinical Use Tetrahydrocannabinoids (THC) are the THC alters mood and perception. This Clinically, THC is used to manage primary psychoactive components in altered state can alleviate nausea and chemotherapy-induced nausea and marijuana. They exert inhibitory vomiting by impacting the brain's vomiting. It's also used for other effects on the brain's reticular pathways related to these sensations. conditions like anorexia in HIV/AIDS formation, thalamus, and cerebral patients. cortex. Tetrahydrocannabinoids: Dronabinol (Marinol) Mechanism of Action Chemotherapy- Induced Nausea Binds to cannabinoid receptors. Reduces nausea Effective in treating nausea and vomiting. and vomiting. Caused by chemotherapy. AIDS-Related Anorexia Important Considerations Can stimulate appetite. Aids Requires careful monitoring. in weight gain for patients. Potential for side effects. Miscellaneous Antinausea Drugs Phosphorated Carbohydrate Solution Emetrol is a mint-flavored oral solution. It's used off-label for morning sickness. Mint Flavor The mint flavor may improve palatability. This can increase patient compliance. Morning Sickness Effective for nausea and vomiting. It's considered relatively safe. Adverse Effects Drowsiness Dry Mouth Many antiemetics cause drowsiness. Anticholinergic effects are common. Blurred Vision Constipation Antihistamines can cause blurred vision. Some antiemetics cause constipation. Adverse effects vary by drug. They stem from receptor blockade. Herbal Products: Ginger Ginger for Nausea Adverse Effects and Interactions Ginger is a natural remedy. It's used to treat nausea and Possible side effects include mild gastrointestinal upset. vomiting. Rarely, skin reactions may occur. Conditions treated include chemotherapy-induced Ginger can increase the absorption of some oral nausea, morning sickness, and motion sickness. medications. It may also increase bleeding risk with anticoagulants. Nursing Implications Assessment Medications Thoroughly assess the Carefully review the patient's history of nausea patient's current and vomiting. Note any medications. Identify precipitating factors. potential drug interactions. Contraindications Drowsiness Warning Check for contraindications. Warn patients about Assess for allergies and drowsiness. Advise against other relevant health operating machinery. information. Nursing Implications (Cont.) Patient Education Monitoring Medication Timing Educate patients on potential drug Closely monitor patients for both Administer antiemetics 30-60 minutes interactions, such as with alcohol. therapeutic and adverse effects. before chemotherapy. This timing is Emphasize slow position changes to Observe for nausea, vomiting, and crucial for effectiveness. prevent hypotension. other symptoms.