Nausea
unpleasant feeling that often precedes vomiting
Emesis
forcible emptying of gastric, and occasionally intestinal contents
Antiemetic drugs
used to relieve nausea and vomiting
Voming center
Medulla
Chemoreceptor trigger zone
gastrointestinal tract, labrynth (inner ear), and Cerebral Cortex
Antiemetic and Antinausea Drugs Mechanisms of action
many different mechanisms f action, most work by bocking one of the vomiting pathways, thus blocking the stimulus that induces vomting
Antiemetic and Antinausea indications
specific indications vary per class of antiemetics, general use for each type: prevention and reduction of nausea and vomiting
Antiemetic and Antinausea drugs
Anticholinergics, Antihistamine, antidopaminergics, prokinetic, serotonin blockers, tertahydrocannabinoids
Anticholinergics Drugs mechanisms of action
bind to and vlock acetylcholine receptors in the inner ear (labrynth), blocks transimttion of nauseating stimuli to CTZ, also block transmission of nauseating stimuli from the reticular formation to the VC Example: Scopolamine (also used for motion sicken
Antihistamine Drugs Mechanisms of Action
inhibits ACH by binding to H1 receptors, prevents cholinergics stimulation in vestibular and reticular areas, thus preventing nausea and vomting, also used for motion sickness, nonproductive cough, allergy symptoms, sedation Examples: dimenhydriinate (Dra
Antidopaminergic Drugs Mechanisms of action
block dopamine receptors on the CTZ. also used for psychotic disorders, intractable hiccups Examples: prochloperazine (Comazine), promethazine (Phenergan), droperidol (Inapsine) use is controvrisla because of associated cardiac dysrhythmia
Prokinetics Drugs mechanisms of action
block dopamine in the CTZ, case CTZ to be desnsitized to impulses it recieves from the GI tract, also stimulates peristalsis in GI tract, inhacning emptying of stomach contents, also used for GERD, delayed gastric emptying Exmaple: metoclopramide (Reglan)
Seratonin blockers Mechanisms of Actions
bleck seratonin receptors in the GI tract, CTZ and VZ, used for nausea and vomiting in patients recieving chemotherapy and for postoperative nausea and vomting Example: dolasetron (Anzemet), granisetron(Kytirl), ondanestron (Zofran), palonsetron (Aolxil)
Tetrahydrocannabinoids mechanism of action
major psychoactive substance in marijuana, inhibitory effects on reticular formation, thalamus, cerebral cortex, after mood and body's perception of its surroundings Example: Dronabinol (Marinol), used for nausea and vomiting associated with chemotherapy,
Anticholinergics Adverse effects
dizziness, drowsiness, disorientation, tahchycardia, blurred vision, dlated pupils, dry mouth, difficult urination, constipation
Anthistamines Adverse effects
dizziness, drowsiness, confusion, blurred vision, dilated pupils, dry mouth, urinary retention
Antidopaminergics Adverse effects
orthostatic hypotension, EKG changes, tachycardia, headache, blurred vision, dry eyes, urinary retnetion, dry mouth, nausea/vomiting, anorexia, constipation
Prokinetics adverse effects
hypotension, tachycardia, sedation, fatigue, restlessness, headache
Seratonin Blockers Adverse effects
headache, diarrhea, rash, bronchospasms
Tetrahydrocannabinoids adverse effects
drowsiness, dizziness, anxiety, confusion, euphoria, visual disturbances, dry mouth
Ginger
herbal product used for nausea and vomiting including that caused by chemotherapy, morning sickness, and motion sickness
adverse effects; nausea and vomiting, skin reactions
Drug interactions: may increase absorption of oral medications, increase bleeding
Nursing Implication of Antiemetic and Antinausea medicines
assess complete nausea and vomting history, including precipitating factors, weight loss, baseline vitals, hydration status, any lab results
assess current medications (OTC, herbals, RX, social drugs)
assess for contraindications and potential drug intera