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Flashcards in Nausea and Vomiting Deck (63)

What is nausea?

Unpleasant awareness of the urge to vomit
Proceeded or accompanied by increased perspiration, salivation, tachycardia, increased respiration rate, lack of appetite and headache


What is vomiting?

Forceful expulsion of stomach contents
Acute vs delayed (acute is within 24 hours, delayed is after 24 hours)
Breakthrough (when you're taking something and you're still vomiting)


What is retching?

Dry heaves
Strong, involuntary and unsuccessful effort to vomit


Describe the pathophysiology of nausea and vomiting

The area that coordinates vomiting is called the vomiting centre is called the vomiting centre
The vomiting centre receives the integrates afferent impulses and stimuli
The vomiting centre then sends efferent impulses to salivation centre, respiratory centre, pharyngeal , GI and abdominal muscles


What are the neurotransmitters and receptors involved in nausea and vomiting?

Unknown neurotransmitters


What are the centre involved with nausea and vomiting?

Chemoreceptor trigger zone (CTZ)
Cerebral cortex and limbic system
Vestibular function disturbances
Sensory receptors in GI tract


What is nausea and vomiting associated with?

It is a symptom of over 75 different conditions
Nausea and vomiting is associated with motion sickness, post chemotherapy nausea and vomiting, pregnancy-associated nausea and vomiting, post operative nausea and vomiting, medication-induced nausea and vomiting


What causes visceral afferent stimulation?

Mechanical obstruction
Motility disorders
Peritoneal irritation
Topical GI irritants


What are CNS disorders that can cause nausea and vomiting?

Vestibular disorders
Increased intracranial pressure


What causes CTZ irritation?

Initiated or withdrawn drugs
Systemic disorders


What needs to be considered while doing a differential diagnosis of motion sickness?

Vestibular disease
Metabolic disorders
Toxin exposures
Mountain sickness


What are complications due to vomiting?

Electrolyte imbalance
Acid-base imbalance
Dental caries
Esophageal rupture


What are signs and symptoms of dehydration in adults?

Increased third
Decreased urination
Feeling weak or light-headed
Dry mouth/tongue


What are signs and symptoms of dehydration in children?

Dry mouth and tongue
Sunken and/or dry eyes
Sunken fontanelle (soft spot)
Decreased urine output (i.e., dry diapers for several hours)
Dark urine
Fast heartbeat
Thirst (drinks extremely eagerly)
Absence of tears when crying
Decreased skin turgor (increased axillary skin folds, "doughy" skin (may indicate hypernatremia), when pinched, skin returns to normal very slowly)
Unusual listless, sleepiness, decreased alertness or tiredness (body if "floppy", lightheadedness when sitting/standing, difficulty in waking child up)
Weight loss


Describe weight loss as a sign/symptom of dehydration in children

Noticeable decrease in "tummy size"
Clothes/diapers fit loosely
Less than 3% body weight loss = minimal/no dehydration
3-9% body weight loss = mild/moderate dehydration
Over 9% body weight loss = severe dehydration


How can nausea and vomiting be classified?



Describe simple nausea and vomiting

Occasional episodes, self-limiting or relieved by minimal use of an anti-emetic
Consequences are mild
Not related to administration or exposure to noxious agents


Describe complex nausea and vomiting

Symptoms are not adequately or readily relieved by single anti-emetic
Consequences are severe
Caused by noxious agents or psychogenic events


Describe motion sickness

Very common condition; 58% of children experience car-sickness and up to 100% of travellers on ships experience seasickness
Greatest incidence occurs from ages 3 to 12 (children under 2 are immune to motion sickness)
Females are more prone than males (especially during pregnancy and menstruation)


What are the signs and symptoms of motion sickness?

Feeling restless
Feeling warm
Excessive salivation
Breaking into a cold sweat
Loss of appetite


What are risk factors for motion sickness?

Type of travel (boat > air > car > train)
Stimulus intensity and frequency
Duration of directional change
Poor ventilation
Individual predisposition


What are the goals of treatment of nausea and vomiting?

Eliminate or reduce symptoms of nausea
Prevent or reduce the frequency of vomiting
Prevent complications of nausea and vomiting


What are treatment approaches for motion sickness?

Counsel on non-drug methods
Recommend anti-emetic to prevent or treat if needed
Treat children in the same manner as adults (watch for age restrictions of medications)
Rehydrate patient if vomiting occurs or patient is dehydrated


What are pharmacological treatments based on?

Availability (OTC vs Rx)
Previous response
Route of administration
Side effects
Patient preference


What are the non-prescription therapies available for motion sickness?

Dimenhydrinate (DMH; Gravol)
Diphenhydramine (Benadryl)
Scopolamine (Transderm V)
Ginger root (zingiber officinale Roscoe; Gravol - Natural Source)


What are the dimenhydrinate products available?

Liquid 3 mg/ml
Chew tab (15 mg and 50 mg)
Filmkote tab (25 mg and 50 mg)
Softgel caps (50 mg)
Dual relief tab (25 mg IR and 75 mg SR)
Suppository (25 mg, 50 mg and 100 mg)


What are the diphenhydramine products available?

Liquid 6.5 mg/ml
Elixir 12.5 mg/5ml
Chew tab: 12.5 mg
Caplet: 25 mg
Caps: 50 mg


What are dimenhydrinate and diphenhydramine?



What is the mechanism of action of anti-emetics/anti-histamines?

Block ACh and H-1 receptor centrally
These agents act on H-1 receptors in vomiting centre and on the vestibular afferents. They act on the ACh receptors in the vestibular apparatus


What is the indication for anti-emetics/anti-histamines?

Prevention and treatment of motion sickness (may be used to treat nausea and vomiting due to other causes)


What are the adverse effects of anti-emetics/anti-histamines?

Sedation, dry mouth, constipation, urinary retention, blurred vision, paradoxical excitation in children


What are the scopolamine products available?

Adhesive disk (contact surface 2.5 cm square)
Scopolamine 1.5 mg (programmed to release in vitro 1 mg scopolamine over 3 days)


What is scopolamine?



What is the mechanism of action of scopolamine?

Block ACh in vestibular apparatus


What is the indication of scopolamine?

Prevention of motion sickness


How should scopolamine be administered?

Apply one patch a dry, hairless area of post-auricular skin approximately
Initial dose should be at least 4-12 hours before antiemetic effect is required
If therapy is required for longer periods, one disc should be remove after 72 hours and a second disc applied behind the other ear


What are the adverse effects of scopolamine?

Sedation, constipation, dry mouth, blurred vision, rash, allergic contact dermatitis, eye irritation (if they touch the eyes), disorientation, delirium, elderly are at increased risk for CNS effects


What are the ginger root products available?

Filmkote tab: ginger root extract (1:25) 20 mg equivalent to dried root 500 mg
Lozenges: ginger root extract (1:25) 20 mg equivalent to ginger dried root 500 mg


What is ginger root?

Herbal anti-emetic


What is the mechanism of action of ginger root?

Unknown. No effect on ACh receptor (more peripheral effect)


What is the indication for ginger root?

Prevention and treatment of motion sickness


How should ginger root be administered for the prevention of motion sickness?

2 tabs or lozenges at least 30 minutes before departure


How should ginger root be administered for the treatment of motion sickness?

2 tabs or lozenges QID 1-3 times a day
Do not exceed 6 tabs/lozenges a day


What are the adverse effects of ginger root?

Ginger has been reported to exacerbate symptoms in patients with acute inflammatory skin diseases and can cause contact dermatitis


What are the side effects of OTCs for the prevention and treatment of motion sickness? (with the exception of ginger)

Dizziness (DMH


What are drug interactions and precautions of OTCs for the treatment and prevention of motion sickness? (except ginger root)

Be careful before driving/operating heavy machinery
Do not combine medication with alcohol
Additive SE with sedatives, CNS and anti-cholinergic medications
Use with caution in the elderly
DMH is the drug of choice for 2-12 years old


What are contraindications for OTCs for the prevention and treatment of motion sickness? (except ginger root)

Use only under the supervision of a physician if the patient has: seizure disorder, respiratory condition (COPD, asthma), difficulty with urination due to BPH, narrow angle glaucoma, obstructive bowel disease
Avoid if breastfeeding


Can OTCs for motion sickness be used in pregnancy?

DMH has been used but should only be used under advice of a physician
Promethazine has been used but should only be used under advice of a physician
Use of ginger is controversial and should only be used under the advice of a physician
Diclectin (doxylamine/pyridoxine) should only be used under the advice of a doctor (prescription product)


What is promethazine used for?

Used in the prevention and treatment of motion sickness
Usually used as an alternative in patients with refractory nausea or if DMH is ineffective


What is the MOA of promethazine?



What is the dosing of promethazine for an adult?

25 mg PO BID with first dose 30-60 minutes before departure and repeat dose in 8-12 hours PRN


What is the dosing of promethazine for a child over 2?

0.5 mg/kg (max dose 25 mg/dose) with first dose 30-60 minutes before departure and repeat dose in 12 hours PRN


What is the onset of promethazine?

30 minutes


What does promethazine interact with?

CNS depressants


What are contraindications of promethazine?

Lower respiratory tract symptoms (includes asthma)


What are side effects of promethazine?

Sedation, somnolence, extrapyramidal symptoms, dry mouth, constipation, blurred vision


What are non-drug options?

Acupressure wristband (Sea Bands)
Acustimulation wristband (ReliefBand)


What are acupressure wristbands?

They are a mechanical device; a cloth wristband with a plastic stuff. They are worn on both wrists. They are washable and can be used up to 5 times. Costs about 10$


What are acustimulation wristbands?

They are electronic devices (resembles a sports watch) worn on the underside of 1 wrist. They have 5 settings. They are available as disposable type which lasts 144 hours and non-disposable type that has replaceable batteries.
They cost 75-145$. They are not recommended for people with pacemakers


What is non-drug advice?

Avoid/decrease exposure to precipitating factors
If exposure is unavoidable, then avoid eating a large meal within 3 hours of travel, avoid dairy products and foods high in protein, calories or sodium before travel. Avoid alcohol, smoking and disagreeable odours (improve ventilation). Avoid visual stimuli that commonly precipitate motion sickness, such as reading and watching videos during travel. While traveling focus on stable external object or the horizon. While on a boat, stay in a central location least susceptible to motion. While in a vehicle, sit on the front seat with a clear forward view (drive if possible)


What are monitoring parameters?

Monitor patient whenever he/she is exposed to stimulus
Endpoint of therapy: minimal or no nausea and no vomiting
Action if endpoint is not achieved: increase the dose and ensure it is given 30-60 minutes before, or refer to a doctor
If the patient experiences an intolerable adverse effect, consider dosage reduction, switching to another agent, relying on non-drug measures alone


What are red flags for adults?

Fever and/or diarrhea present
Suspected food poisoning that is severe and/or does not clear up in 12 hours
Fever, severe abdominal pain in middle or right lower quadrant or severe right upper quadrant (especially after eating fatty foods)
If the duration is longer than 3 days
Patient is severely dehydrated
Head trauma, numbness, tingling, blurred vision or altered state of consciousness
Stiff neck, sensitivity to light
Urine ketones and/or high BG accompanied by signs of dehydration in patients with DM
Blood in vomit
Significant weight loss
Dark urine or yellowing of the skin/eyes
Psychogenic/drug/chronic disease-induced nausea and vomiting
Patients with glaucoma, BPH, chronic bronchitis, emphysema or asthma
Pregnancy or breastfeeding


What are red flags for children?

Child is under 2 years old
Signs of dehydration are present
Vomiting lasting over 6 hours
Child refuses to drink
Lack of urination in past 8-12 hours
Stiff neck
Weight loss
Appears lethargic, unusually sleepy, listless or crying, altered level of consciousness
Vomit is red, black or green
Vomiting occurs with each feeding
Vomiting is repeatedly projectile and/or has continued over 6 hours
Vomiting is associated with diarrhea, distended abdomen, fever, or sever head injury
Poisoning is suspected or head trauma
Vomiting occurs with recurrent, severe, acute abdominal pain
Child is high risk (DM, CNS disease, hernia)