Download Ch. 26-Drugs Used to Treat Nausea, Vomiting, Constipation and

Nausea and Vomiting
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nausea: sensation of abdominal discomfort that may lead to the
urge or need to vomit
vomiting (emesis): expelling stomach contents through the
mouth, signals illness or injury
vomitus (emesis) is the food and fluid expelled from the
stomach through the mouth
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nausea may occur without vomiting and vice versa
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often nausea and vomiting occur together
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retching: involuntary, labored, spasmodic contractions of the
abdominal and respiratory muscles without vomitus, aka “dry
heaves”
Structures Involved in Vomiting (box 26-1)
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vomiting center (VC) is located in medulla, it coordinates the
vomiting reflex
nerves from sensory receptors in the pharynx, stomach, intestines
and other tissues connect directly with the VC through the vagus
and splanchnic nerves. Nerves produce vomiting when
stimulated
VC also responds to stimuli from other tissues-cerebral cortex,
vestibular apparatus of inner ear, and blood
stimuli travel to the chemo-receptor trigger zone in the medulla,
activates the VC to induce vomiting
when VC is stimulated nerve impulses are sent to salivary, vasomotor and respiratory centers
reflex begins with sudden, deep inspiration that increases
abdominal pressure, abdominal muscles contract
soft palate rises and the epiglottis closes, this prevents aspiration of
vomitus into lungs
pyloric sphincter contracts and cardiac sphincter and esophagus
relax, stomach contents are expelled. Saliva increases to aid
expulsion
pallor, sweating and tachycardia also occur with vomiting
Common Causes of Nausea and Vomiting box (26-2)
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chemotherapy
drug therapy
emotional disturbances
GI disorders (gastritis, liver, gallbladder, pancreatic diseases)
infection
mental illness
motion sickness
over-eating
pain
pregnancy
radiation therapy
stomach irritation by certain foods/liquids
surgical procedures
unpleasant sights/odors
Constipation:
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constipation: passage of hard, dry stool
person usually strains to have a bowel movement
stools are large or marble-size
large stools cause pain as they pass through anus
constipation occurs when feces move slowly through the
bowel, this allows more time for water absorption
common causes of constipation:
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low-fiber diet
ignoring urge to defecate
decreased fluid intake
inactivity
drugs
aging
certain diseases
constipation cont….
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dietary changes, fluids, and activity prevent or relieve
constipation, so do drugs and enemas
if not relieved constipation can lead to fecal impaction
fecal impaction: prolonged retention and build-up of feces in
rectum
feces are hard or putty-like, person cannot defecate, more
water is absorbed from the already hard feces
liquid feces pass around hardened fecal mass in the rectum,
the liquid feces seep from the anus
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Diarrhea:
diarrhea: frequent passage of liquid stools, move
through intestines rapidly, reduces time for liquid
absorption
abdominal cramping, nausea and vomiting may
occur
causes: infections, drugs, irritating foods, microbes in
food and water
diet and drugs are ordered to reduce peristalsis
fluid lost through diarrhea needs to be replaced,
otherwise dehydration occurs
person has pale or flushed skin, dry skin, and a
coated tongue
urine is dark and scant in amount (oliguria)
diarrhea cont…
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thirst, weakness, dizziness and confusion also occur
falling blood pressure and increased pulse and
respirations are serious signs
death can occur
nursing process focuses on meeting persons fluid
needs
microbes can cause diarrhea, preventing spread of
infection is important (follow standard
precautions)
Focus On Older Persons
Drugs Used to Treat Nausea, Vomiting, Constipation
and Diarrhea
Older persons are at risk for dehydration from diarrhea.
the amount of body water decreases with aging.
Many diseases common in older persons affect body
fluids. So do many drugs. Report signs of diarrhea at
once. Ask the nurse to observe the stool. Death is a
risk when dehydration is not recognized and treated
Delegation Guidelines
Drugs Used to Treat Nausea, Vomiting, Constipation and
Diarrhea:
Some drugs used to treat nausea, vomiting, constipation
and diarrhea are given parenterally- by intramuscular or
intravenous injection. Because you do NOT give
parenteral dose forms, they are NOT included in this
chapter. Should a nurse delegate the administration of
such to you, you must:
- remember that parenteral dosages are often very
different from dosages other routes
-Refuse the delegation. Make sure to explain why. Do
NOT just ignore the request. Make sure the nurse knows
that you cannot give drug and why
Drug Therapy for Nausea and Vomiting
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control of vomiting is important to:
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relieve the distress caused by vomiting
prevent aspiration of stomach contents into lungs
prevent dehydration
prevent electrolyte imbalance
treatment is directed at the cause (box 26-2)
treatment may involve non-drug measures and drugs
anti-emetics are drugs used to treat nausea/vomiting,
generally more effective if given before onset of nausea
most anti-emetics do one of the following:
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suppress action of the vomiting center
inhibit impulses going to or from the VC
Drug Therapy for Nausea and Vomiting
Dopamine Antagonists:
 inhibits dopamine receptors that are part of pathway to
VC, dopamine receptors in other parts of brain are
blocked too
 drugs in this class are phenothiazines, used for mildmoderate nausea and vomiting associated with:
anesthesia
 surgery
 radiation therapy
 chemotherapy
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Butyrophenones: used as anti-emetics in surgery and
chemo, sedation is a side-effect
metoclopramide (Reglan): also acts on receptors in GI tract,
useful for persons with GI cancers, gastritis, peptic ulcer,
radiation sickness and migraines
Drug Therapy for Nausea and Vomiting cont…
Assisting With the Nursing Process
dopamine antagonists:
ASSESSMENT: observe type, amount and frequency of emesis,
observe persons level of alertness
PLANNING: see table 26-1 (pg. 328-329) “Dose Forms”
IMPLEMENTATION: see table 26-1 (pg. 328-329) for “Adult
Dosage Range
EVALUATION:
-see ch. 15 for phenothiazines
-see ch. 15 for haloperidol
-see ch. 25 formetoclopramide (Reglan)
Drug Therapy for Nausea and Vomiting cont…
Serotonin Antagonists:
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block receptors in medulla and GI tract that cause nausea and vomiting
used to treat emesis associated with: chemo, radiation and post-operative
nausea/vomiting
Assisting With the Nursing Process
serotonin antagonists:
ASSESSMENT: observe type, amount and frequency of emesis,
observe persons level of alertness
PLANNING: see table 26-1 (pg. 328-329) “Dose Forms”
IMPLEMENTATION: see table 26-1 (pg. 328-329) for “Adult Dosage
Range
EVALUATION:
-headache, diarrhea, constipation: usually mild
-sedation: provide for safety
Drug Therapy for Nausea and Vomiting cont…
Anti-Cholinergic Agents:
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motion sickness likely results from stimulation of structures in the inner
ear
stimuli are transmitted to areas near VC
excess acetylcholine is present
these drugs are used to counter-balance the excessive amounts of
acetylcholine present
Assisting With the Nursing Process
Anti-Cholinergic Agents :
ASSESSMENT: observe type, amount and frequency of emesis,
observe persons level of alertness
PLANNING: see table 26-1 (pg. 328-330) “Dose Forms”
IMPLEMENTATION: see table 26-1 (pg. 328-330) for “Adult Dosage
Range
EVALUATION: see Ch. 14
Drug Therapy for Nausea and Vomiting cont…
Cortico-Steroids:
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used for nausea and vomiting, are effective alone or when used with other
anti-emetics, may help the person accept and control emesis
Assisting With the Nursing Process
Cortico-Steroids:
ASSESSMENT: observe type, amount and frequency of emesis,
observe persons level of alertness
PLANNING: see table 26-1 (pg. 328-330) “Dose Forms”
IMPLEMENTATION: see table 26-1 (pg. 328-330) for “Adult Dosage
Range
EVALUATION: side effects do not occur often
Drug Therapy for Nausea and Vomiting cont…
Benzodiazepines:
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act as anti-emetics through a combination of effects, they do the following
cause sedation, reduce anxiety, depress VC, have an amnesia effect
effective in reducing frequency of nausea/vomiting
Assisting With the Nursing Process
Benzodiazepines :
ASSESSMENT: observe type, amount and frequency of emesis,
observe persons level of alertness
PLANNING: see table 26-1 (pg. 328-330) “Dose Forms”
IMPLEMENTATION: see table 26-1 (pg. 328-330) for “Adult Dosage
Range
EVALUATION: see ch 15
Drug Therapy for Nausea and Vomiting cont…
Neurokinin-1 Receptor Inhibitor:
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act as anti-emetics used to prevent nausea/vomiting from chemo and
anesthesia
aprepitant (Emend): drug blocks actions of substances that cause
nausea/vomiting, used with cortico-steroid and a serotonin agonist
Assisting With the Nursing Process
aprepitant (Emend):
ASSESSMENT: observe type, amount and frequency of emesis
PLANNING: see table 26-1 (pg. 328-330) “Dose Forms”
IMPLEMENTATION: see table 26-1 (pg. 328-330) for “Adult Dosage
Range
EVALUATION: report and record:
-Tiredness, nausea, hiccups, constipation, diarrhea, loss of appetite,
headache, hair loss. Drug is taken for up to 3 days, minimal side
effects
Drug Therapy for Constipation and Diarrhea
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laxatives: substances that cause evacuation of the
bowel
anti-diarrheals: drugs that relieve symptoms of
diarrhea
Laxatives:
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types of laxatives:
stimulant laxatives: act directly on intestine, cause irritation that
promotes peristalsis and evacuation, both oral (acts in 6-10 hours)
and rectal (acts in 60-90 mins) agents
saline laxatives: draw water into intestine from surrounding
tissues, extra water affects stool consistency and distends the bowel,
peristalsis increases. Usually agents act in 1-3 hours
Lubricant laxatives: contain oils, they lubricate intestinal wall and
soften feces. Allows smooth passage of feces, onset is usually 6-8
hours, may be up to 48 hours. Peristalsis does NOT appear to
increase, useful to prevent constipation in persons who should not
strain during defecation
bulk-producing laxatives: given with a full glass of water, drug
causes water to be retained in feces, increasing the bulk. Increased
bulk stimulates peristalsis, onset usually 12-24 hours
Types of laxatives cont….
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Fecal softeners: draw water into feces which softens it, these do
NOT stimulate peristalsis. May take 72 hours for a soft bowel
movement. These are often call stool softeners, used to prevent
constipation/straining
Bulk forming laxatives: soften and increase fecal mass, used to
control certain types of diarrhea by absorbing the irritating
substance. Substance is then removed from the bowel with
defecation. Agents dispersed into water or juice
Stimulant and saline laxatives: combo of stimulant and saline
laxatives, used to relieve acute constipation. Usually used as a
bowel prep to remove gas and feces before x-rays of examined
kidneys, intestine or gallbladder
Goals of laxatives are:
Relief from abdominal discomfort
Passage of bowel contents within a few hours of administration
Assisting With the Nursing Process
laxatives:
ASSESSMENT: ask about the persons bowel elimination patterns, ask person
to describe any abdominal pain
PLANNING: see table 26-2(pg. 333)
IMPLEMENTATION: follow directions on MAR and container, give
adequate water with bulk-forming agents. Without enough water, they
can cause esophageal, gastric, intestinal, or rectal obstruction
EVALUATION: report and record:
-Griping (gripping), abdominal discomfort. Griping: sever and spasm-like
pain the abdomen caused by an intestinal disorder. Can result from
excessive bowel stimulation
-abdominal tenderness, pain, bleeding, vomiting, diarrhea, abdominal
distention. No bowel movement or only a small stool may signal
impaction, or may signal an acute abdomen. This is serious and could
require surgery
Anti-Diarrheal Agents:
2 types of anti-diarrheal agents are:
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anti-diarrheal drugs usually ordered:
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local acting agents: absorb excess water to cause a
formed stool, absorb irritants or bacteria causing the
diarrhea
systemic agents: act through nervous system to reduce
peristalsis and GI motility
when diarrhea is of sudden onset
has lasted 2-3 days and is causing significant fluid loss
when persons with inflammatory bowel disease develop
diarrhea
post-op for diarrhea after GI surgery
goal of therapy is relief from diarrhea and its
discomforts
Assisting With the Nursing Process
Anti-diarrheal:
ASSESSMENT: ask about the persons bowel elimination patterns, ask
person to describe any abdominal pain
PLANNING: see table 26-3(pg. 334-335) for “Oral Dose Forms”
IMPLEMENTATION: see table 26-3(pg. 334-335) “Adult Dosage”
follow directions on MAR and container, give adequate water with
bulk-forming agents. Without enough water, they can cause
esophageal, gastric, intestinal, or rectal obstruction
EVALUATION: report and record:
-abdominal discomfort, nausea, constipation. These may result from
the excessive use of local agents
-prolonged or worsening diarrhea, toxins may be present