DPT IV Exam 3 (chessman)

nausea

unpleasant feeling in the stomach

need to vomit

retching

labored muscle movement

impending vomit

vomiting

forceful expulsion of GI contents

what is a common intraperitoneal cause of nausea/vomiting?

gastroenteritis

what is a common neurologic cause of nausea/vomiting?

balance disorders

what is a common therapy-induced cause of nausea/vomiting?

postoperative (PONV)

symptoms of n/v

simple

self-limiting, resolves spontaneously

complex

not relieved by antiemetics

deteriortation due to fluid and electrolyte losses

signs of n/v

simple

queasiness or discomfort

complex

weight loss, fever, abdominal pain

lab/procedures of n/v

simple

none

complex

serum electrolytes, imaging if warranted

acute CINV

within 24h of therapy

delayed CINV

after 24h of therapy

anticipatory CINV

prior to receiving therapy

breakthrough CINV

occurs despite prophylaxis

refractory CINV

poor response to antiemetics

who has the highest risk of radiology induced nausea and vomiting (RINV)?

total body irradiation

moderate risk of RINV

upper body or abdomen and craniospinal

low risk of RINV

brain, head and neck, thorax, and pelvic

minimal risk of RINV

extremity or breast

balance disorders

vertigo

dizziness

motion sickness

causes - many (including post-concussion)

treatments for balance disorders

antihistaminic-anticholinergic agents

dimenhydrinate (Dramamine®) - OTC

diphenhydramine (Benadryl®) - OTC

hydroxyzine (Atarax®, Vistaril®) - Rx

meclizine (Antivert®) - OTC, Rx

scopolamine patch (Transderm-Scop®) - Rx

trimethobenzamide (Tigan®) - Rx

how is vertigo/dizziness treated?

give once to several times daily before motion

how is motion sickness treated?

place scopolamine patch on several hours before anticipated motion exposure

give 1st generation antihistamines around 1 hour before motion

true or false: 2nd generation antihistamines, ondansetron, and ginger are effective with treating motion sickness

false

adverse effects of the treatment for balance disorders

drowsiness

confusion

blurred vision

dry mouth

urinary retention

you should caution treatment of balance disorders in the elderly due to the adverse effects and you should look where?

the Beers criteria

What percent of pregnant women experience nausea/vomiting?

A. 10-20%

B. 25-30%

C. 40-50%

D. 50-80%

D

what is the extreme vomiting during pregnancy called?

hyperemeseis gravidarum

first line therapy for pregnancy associated N/V

pyridoxine (B6) alone or with doxylamine

cause of gastroenteritis

inflammation of the GIT mucus membranes

what is the n/v of gastroenteritis due to?

chemotoxin

viruses (70%)

rotavirus, adenovirus

bacteria

Salmonella, Campylobacter, Shigella, Yersinia

treatment of gastroenteritis

hydration/rehydration is KEY

first line: oral rehydration for fluid and electrolyte correction

supportive care with IV therapy, if severe

antiemetics may be used, if severe

5-HT3 receptor antagonists are preferred

true or false: corticosterioids are effective in gastroenteritis

false

MOA of HT-3 receptor antagonists

selective antagonism of 5-HT3 - receptors in peripheral and central nervous system and EC cells on sensory vagal fibers in the gut wall

first line 5-HT3 receptor antagonist agent

ondansetron 0.1- 0.15 mg/kg up to 4 mg

PO tablets, ODT, IV

high efficacy as it improves the success of oral rehydration

adverse effects are low but caution with repeated dosing, DDIs, prolonged QTc

other 5-HT3 receptor antagonist agents

granisetron, palonosetron

MOA of phenothiazines

antagonism of dopamine binding at D2 receptors in the ctz and nts

promethazine

0.25- 1 mg/kg IV, IM, PO, PR up to 25 mg every 4-6 hours

contraindicated in children < 2 years of age

metoclopramide

0.1 mg/kg up to 10 mg IV, IM, PO

high frequency of extrapyramidal reactions

why should we caution promethazine in all patients?

CV hypotension

respiratory distress from sedation

antihistamines

dimenhydrinate 1.25 mg/kg up to 50 mg

limited efficacy and highly sedative

post operative nausea/vomiting and post discharge nausea/vomiting (PONV/PDNV) occurs in how many patients during the first 24-48h after anesthesia, including PACU?

25-30%

what should dictate the treatment of PONV/PDNV?

risk factors

complications of PONV

decreased patient satisfaction and patient discomfort

elevated HR, BP, CVP, intrathoracic pressure

apfel scoring system

for adults

female gender: 1

H/O PONV or motion sickness: 1

non-smoker: 1

postoperative opioid use: 1

0-1 on the apfel scoring system

low risk

2-3 on the apfel scoring system

medium risk

>3 on the apfel scoring system

high risk

eberhart scoring

for *pediatrics*

surgery > 30 mins:1

age > 3 years: 1

strabismus surgery: 1

history of POV or PONV in relatives: 1

0-1 eberhart scoring

low

2-3 eberhart scoring

medium

>3 eberhart scoring

high

strategies for preventing PONV

avoid general anesthesia

avoid nitrous oxide

avoid volatile anesthetics

use propofol (3.5x ↓ in adults; 5.7x ↓ in children)*

minimize perioperative opioids

maintain adequate hydration

administer prophylactic agents in moderate-to-high risk patients

if at low risk (0-1) for PONV risk factors, what should you do?

wait and see

if at medium risk (2-3) for PONV risk factors, what should you do?

1-2 interventions

if at high risk (>3) for PONV risk factors, what should you do?

>2 interventions

prophylaxis and treatment agents for PONV

regional anesthesia

propofol

5HT3 antagonists

NK1 Antagonists

butyrophenones

phenothiazines

anticholinergics

antihistamines

corticosteroids

non-pharmacologic treatment for PONV

dietary changes

treat underlying cause

chewing gum

accupressure bands

dosing of 5-HT3 receptor antagonists

ondansetron (Zofran) 4 mg IV

granisetron (Kytril) 0.35-3 mg IV

palonosetron (Aloxi) 0.075 mg IV

when are ondansetron and granisetron given?

at then end of surgery

when is palonsetron given?

at the start of surgery

pearls of 5 HT-3 receptor antagonists

ondansetron is the gold standard

ondansetron and granisetron affect the QTC interval

palonsetron does NOT affect the QTc interval and has the longest half

MOA of neurokinin-1 receptor antagonists

bind to the NK1 receptor blocking substance P to prevent emetic signal from being transmitted

dosing of neurokinin-1 receptor antagonists

aprepitant - 40 mg PO / 80 mg for high-risk

fosaprepitant (Emend) and rolapitant (Varubi) – CINV only

when are neurokinin-1 receptor antagonists given?

within 3 hours prior to anesthesia induction

pearls of neurokinin-1 receptor antagonists

aprepitant - potential DDIs (moderate CYP3A4 inhibitor and CYP2C9 inducer)

significantly more effective than ondansetron alone for prevention at 24 and 48 hr after surgery

MOA of corticosteroids

unknown for nausea/vomiting

dosing for corticosteroids

dexamethasone 4-8 mg IV

methylprednisolone 40 mg IV

when are corticosteroids given?

at the end of surgery (steroid)

pearls of corticosteroids

increased blood glucose concentrations

MOA of butyrophenones

block dopamine stimulation (D2 receptor) in the CTZ

dosing of butyrophenones

haloperidol 0.5-2 mg IV or IM

droperidol 0.625-1.25 mg IV

when are butyrophenones given?

at the end of surgery (butyrophenones)

pearls of butyrophenones

QTc prolongation (US boxed warning sudden cardiac death - droperidol)

not recommended for 1st line therapy

MOA of anticholinergics

act on muscarinic receptors in the vomiting

anticholingeric medication used for N/V

scopolamine patch

when are anticholingeric medications used?

apply evening before surgery or at least 2-4 hr before anesthesia

pearls of anticholinergic medications

dry mouth

dizziness

MOA of phenothiazines

block dopamine receptors in the CTZ

dosing of phenothiazines

promethazine 12.5 - 25 mg IV or IM

perphenazine 2.5-5 mg IV or IM

metoclopramide 25-50 mg PO

when are phenothiazines given?

at the end of surgery (phenothiazines)

pearls of phenothiazines

may cause sedation, extrapyramidal symptoms, cardiovascular side effects

remember: CI if < 2 years old

amisulpride

for prevention: at time of induction alone or with an agent of another class

for rescue: after failed prophylaxis with another class

dosage: 5 mg IVP (ppx); 10 mg IVP (treatment)

SE: chills, hypokalemia, procedural hypotension, abdominal distention, infusion site pain

avoid with eGFR < 30

dose- and concentration-dependent QTc prolongation (avoid with droperidol)

avoid with levodopa

pump and dump for lactating women for 48 hr

monitoring: ECG

What percent of pregnant women experience nausea/vomiting?

A. 10-20%

B. 25-30%

C. 40-50%

D. 50-80%

D

What percent of patients experience PONV?

A. 10-20%

B. 25-30%

C. 40-50%

D. 50-80%

B

What are the 2 DOCs for pregnancy-induced N/V?

Based on risk factors who would be more likely to experience PONV?

A. 28-year-old female non-smoker having a gynecological surgery

B. 65-year-old female non-smoker having laparoscopic surgery

C. 22-year-old male smoker having orthopedic surgery

D. 5-year-old male having ear surgery which will last < 30 min

A

You are the OR pharmacist. A physician calls for your recommendation on an antiemetic for a 46-year-old woman who is in the PACU s/p knee surgery. She received PO promethazine and IV ondansetron for PONV prophylaxis. She is now experiencing N/V. What is the best recommendation?

A. Palonosetron

B. Metoclopramide

C. Aprepitant

D. Haloperidol

D

Which of the following antiemetics can cause QTc prolongation?

A. Ondansetron

B. Dexamethasone

C. Dimenhydrinate

D. Droperidol

E. Amisulpride

A, D, E