Term
| what are the different causes of n/v? |
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Definition
| motion sickness stimulates the vomiting center (ACh) and chemotrigger receptor zone (DA). drugs (antineoplastics), radiation, diseases (CA), and stress (pre-op) stimulate the CTZ. |
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Term
| how are anticholinergics used for n/v? |
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Definition
| anticholinergics work particularly well for n/v due to labyrinthine disorders/motion sickness. |
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Term
| which anticholinergics are used for n/v? ADRs? |
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Definition
| scopolamine, trimethobenzamide, diphenidol (slight anticholinergic, inhibits vestibular apparatus + CTZ) and the antihistamines: buclizine, cyclizine (better in pregnancy), diphenhydramine, dimenhydrinate, hydroxyzine, and meclizine (worse in pregnancy) are all used. ADRs: confusion, disorientation, hallucinations |
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Term
| how are DA blocking agents used for n/v? what are they? |
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Definition
| DA blocking agents are used especially for drug-induced emesis and include the phenothiazines (chlorpromazine, promethazine, perphenazine, thiethylperazine, prochlorperazine, triflupromazine - two types of compazine suppositories[adult and child]) a butyrophenone derivative (droperidol - similar to haloperidol) and metoclopramide (relaxes GI sphincter). |
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Term
| how are serotonin blocking agents used for n/v? what are they? |
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Definition
| dolasetron, granisetron, ondansetron (orally disintegrating tabs), palonosetron = selective 5-HT3 antagonists. 5-HT3 receptors are located peripherally (vagal nerve terminals) and centrally (CTZ). these are indicated during cancer chemo tx as antineoplastics release 5-HT from enterochromaffin cells of the small intestine (onset of emesis parallels increased levels of urinary 5-HIAA after cisplatin). alosetron is also a serotonin blocking agent which is only indicated for women w/severe diarrhea prominent IBS who failed conventional tx and do not have anatomic/biochemical GI abnormalities (potentially fatal GI ADRs). |
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Term
| when is dronabinol used? what kind of antiemetic is it? |
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Definition
| this delta-9-tetrahydrocannibinol is used for n/v associated w/CA chemotherapy. |
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Term
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Definition
| a drug used for n/v due to anesthesia/sx - unknown MOA, but slight antihistaminic activity and slight anticholinergic activity. |
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Term
| what is phosphorated carbohydrate solution? |
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Definition
| a hyperosmolar carbohydrate solution mixed w/phosphoric acid which has a direct smooth muscle relaxant effect on the GI tract. avoid in DM pts (high carb load). |
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Term
| can corticosteroids be used as antiemetics? |
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Definition
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Term
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Definition
| aprepitant blocks substance P at neurokinin 1 (NK1) receptors in brain; has little or no affinity for 5-HT3 receptors. it is used in combination w/other anti-emetics in tx of n/v associated w/chemotherapy. first FDA-approved tx to prevent delayed n/v many pts experience 24 hrs after recieving therapy. it does induce CYP, OCP pills may have reduced efficacy and pts on anticoagulant therapy need to have blood levels checked after a 3-day regimen. |
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