Logic Circuits and Switching theory

Drug groups used to correct or control vomiting, diarrhea,
and constipation are

the expulsion of gastric contents, has a
multitude of causes, including motion sickness, viral and bacterial infection, food intolerance, surgery, pregnancy, pain, shock, effects of selected drugs (e.g., antineoplastics), radiation, and disturbances of the middle ear that affect equilibrium.

NOTE: Antiemetics can mask the underlying cause of vomiting and should not be used until the cause has been determined,
unless the vomiting is so severe as to cause dehydration and
electrolyte imbalance.

Two major cerebral centers

. The CTZ receives most of the impulses from
drugs, toxins, and the vestibular center in the ear and transmits them to the vomiting center. The neurotransmitter
________ stimulates the CTZ, which in turn stimulates the
vomiting center

a drug with dopamine-like properties, can cause vomiting by stimulating the CTZ

NOTE: Some sensory impulses, such as odor, smell, taste, and gastric mucosal irritation, are transmitted directly to the vomiting
center

The neurotransmitter _________ is also a vomiting stimulant

NOTE: When the vomiting center is stimulated, the motor
neuron responds by causing contraction of the diaphragm,
the anterior abdominal muscles, and the stomach. The glottis
closes, the abdominal wall moves upward, and vomiting
occurs

The major groups of antiemetics

The nonpharmacologic methods of decreasing nausea and
vomiting include

can be purchased as over-the-counter (OTC) drugs. These drugs are frequently used to prevent motion sickness but have minimal
effect on controlling severe vomiting resulting from anticancer agents (antineoplastics), radiation, and toxins.

To prevent motion sickness, the antiemetic should be taken

Selected antihistamine antiemetics, such as dimenhydrinate (Dramamine), cyclizine hydrochloride (Marezine),
meclizine hydrochloride (Antivert), and diphenhydramine
hydrochloride (Benadryl) can be purchased OTC to prevent
nausea, vomiting, and dizziness (vertigo) caused by motion.

is also used to prevent or alleviate allergic reactions
to drugs, insects, and food by acting as an antagonist to histamine1 (H1) receptors.

The side effects of antihistamine antiemetics are similar to
those of anticholinergics:

Several nonprescription drugs such as _________ act directly on the gastric mucosa to suppress vomiting.

a hyperosmolar carbohydrate, decreases nausea and vomiting
by changing the gastric pH; it may also decrease smooth muscle contraction of the stomach.

Patients with Diabetes Mellitus should avoid this drug, Phosphorated carbohydrate solution (Emetrol), because

NOTE: nonpharmacologic methods should be used to alleviate nausea and vomiting during pregnancy, and OTC antiemetics should be avoided.

If vomiting becomes severe and threatens the well-being of
the mother and fetus, an antiemetic such as __________ can be administered, although this drug is classified as pregnancy category C.

Common prescription antiemetics are classified into the following groups:

Antihistamines and anticholinergics act primarily on the vomiting center; they also act by decreasing stimulation of the CTZ and vestibular pathways. The cannabinoids act on the cerebral cortex. Phenothiazines, the miscellaneous antiemetics
(e.g., metoclopramide), and trimethobenzamide act on the CTZ Center

Side effects and Adverse reaction of Antihistamines and Anticholinergics

These agents suppress emesis by blocking dopamine2 receptors in the CTZ.

Common side effects of dopamine antagonists

are used to treat nausea and vomiting resulting from surgery, anesthetics, chemotherapy, and radiation sickness. They act by inhibiting the CTZ.

When used in patients with cancer, these drugs are commonly
given the night before treatment, the day of treatment, and
for 24 hours after treatment.

REMEMBER: Not all phenothiazines are effective antiemetic agents. When prescribed for vomiting, the
drug dosage is usually smaller than when used for psychiatric
disorder

were the first phenothiazines used for both psychosis and vomiting

is the most frequently prescribed antiemetic drug.

a phenothiazine introduced as an antihistamine in the
1940s, has a sedative effect and can also be used for motion
sickness and management of nausea and vomiting.

REMEMBER: Central nervous system
(CNS) depression increases when promethazine is taken with
alcohol, narcotics, sedative-hypnotics, and general anesthetics. Anticholinergic effects increase when promethazine is combined with antihistamines, anticholinergics such as atropine, and other phenothiazines. Promethazine may interfere with urinary pregnancy tests, producing false results.

REMEMBER: The side
effects of phenothiazine antiemetics are moderate sedation,
hypotension, EPS, CNS effects (restlessness, weakness, dystonic reactions, agitation), and mild anticholinergic symptoms (dry mouth, urinary retention, and constipation).
Because the dose is lower for vomiting than for psychosis,
the side effects are not so severe. Promethazine is relatively
free of EPS at antiemetic doses

________ are Butyrophenones, like phenothiazines, block the dopamine2 receptors in the CTZ. They are used to treat postoperative nausea and the vomiting and emesis associated with toxins, cancer chemotherapy, and
radiation therapy.

Like phenothiazines, haloperidol and droperidol are likely to cause ______ if used for an extended time

Butyrophenones, like haloperidol and droperidol may result to hypotension, thus what should be monitored?

Selected benzodiazepines indirectly control nausea and vomiting that may occur with cancer chemotherapy. _____ is the drug of choice

________ effectively provides emesis control ,sedation, anxiety reduction, and amnesia when used in combination with a glucocorticoid and serotonin 5-HT3 receptor antagonist.

Serotonin antagonists suppress nausea and vomiting by
blocking the _____________  in the CTZ and the
_____________ in the upper GI tract.

are the most effective of all antiemetics in suppressing nausea and vomiting caused by cancer chemotherapy– induced emesis or emetogenic anticancer drugs.

Ondansetron(the first serotonin antagonist), granisetron, and dolasetron do not block the DOPAMINE RECEPTORS; therefore, they do not cause

remember: serotonin receptor antagonists are also effective in
preventing nausea and vomiting before and after surgery.

Common side effects of Serotonin Receptor Antagonist

are two agents that are effective in suppressing
emesis associated with cancer chemotherapy

NOTE: Because these glucocorticoids are administered IV and for only a short while, side effects normally associated with glucocorticoids
are minimized.

The active ingredient of Cannabinoids

These agents may be prescribed for patients receiving chemotherapy who do not respond to or are unable to take other antiemetics

Cannabinoids are contraindicated for patients with

can be used as an appetite stimulant for patients
with acquired immunodeficiency syndrome (AIDS)

REMEMBER :Side effects occurring as a result of cannabinoid use include mood changes, euphoria, drowsiness, dizziness, headaches, depersonalization, nightmares, confusion, incoordination, memory lapse, dry mouth, orthostatic hypotension or hypertension, and
tachycardia.

Less common symptoms of cannabinoids are

are in the class of miscellaneous antiemetics, because they do not act strictly as antihistamines, anticholinergics, or phenothiazines

also prevents vertigo by inhibiting impulses to the
vestibular area

The side effects and
adverse reactions of the miscellaneous antiemetics are

REMEMBER: Trimethobenzamide can cause hypotension, diarrhea, and
EPS (abnormal involuntary movements, postural disturbances, and alteration in muscle tone)
miscellaneous antiemetics

remember: Obtain a history of present health problems. Patients
with glaucoma should avoid many of the antiemetics.

patient teaching on antiemetics

Side effects on antiemetics

suppresses emesis by blocking the
dopamine receptors in the CTZ. It is used in the treatment of
postoperative emesis, cancer chemotherapy, and radiation
therapy

High doses of metoclopramide can cause

are drugs used to induce vomiting

There are many ways to induce vomiting without using drugs, such as

REMEMBER: Vomiting should not be induced if caustic substances,such as ammonia, chlorine bleach, lye, toilet cleaners, or battery acid, have been ingested.  Regurgitating these substances can cause additional injury to the esophagus

Remember: To prevent aspiration, vomiting should also be avoided if petroleum distillates are ingested; these include gasoline, kerosene, paint thinners, and lighter fluid. Activated charcoal is given when emesis is contraindicated.

Ipecac syrup should not be administered ROUTINELY in the
management of poisoned individuals

Ipecac is considered appropriate in isolated cases for the patient who is alert and if administered within ________ of poisoning

Ipecac syrup induces vomiting by

Ipecac should be taken with a

The onset of emesis production
following administration of ipecac syrup is usually _____
minutes.

When vomiting is not induced, patients should be
treated with an _____, such as activated charcoal, or
gastric lavage.

Individuals with bulimia and
anorexia nervosa often abuse ipecac, which may lead to

(frequent liquid stool) is a symptom of an intestinal
disorder.

causes of diarrhea include:

Antidiarrheals should not be used for more than __ days and
should not be used if _____ is present.

The loss of bicarbonate places the patient at risk for developing metabolic acidosis

Patients with diarrhea should avoid ___ products and
foods rich in ____.

Nonpharmacologic measures in diarrhea

Traveler's Diarrhea, also called acute diarrhea, is usually caused

Traveler’s diarrhea can be reduced by

The antidiarrheals are classified as

decrease intestinal motility, thereby decreasing peristalsis.

a common side effect of opium preparations.

Opium antidiarrheals can cause CNS depression when taken with

The duration of action of opiates
is approximately

is an opiate that
has less potential for causing drug dependence than other
opiates such as codeine

is an active
metabolite of diphenoxylate, but it is more potent than diphenoxylate

Diphenoxylate and difenoxin are combined with _____ to
decrease abdominal cramping, intestinal motility, and hypersecretion

Diphenoxylate with atropine (Lomotil) is frequently prescribed for _________, and difenoxin with atropine (Motofen) is prescribed to treat ______

is structurally related to diphenoxylate but causes less CNS depression than diphenoxylate and difenoxin and it protects
against diarrhea, reduces fecal volume, and decreases intestinal fluid and electrolyte losses

Patients with _______ should not
take products containing diphenoxylate, difenoxin, or loperamide

e. Children and older adults who take diphenoxylate are
more susceptible to _________ than other age
groups.

act by coating the wall of the GI tract and adsorbing bacteria or toxins that cause diarrhea.

.Adsorbent antidiarrheals include:

REMEMBER: Bismuth subsalicylate (Pepto-Bismol) is considered an adsorbent because it adsorbs bacterial toxins. Pepto-Bismol can also be used as an antacid for gastric discomfort. Pepto-Bismol is an OTC drug commonly used to treat traveler’s diarrhea

are prescription drugs that have been used to treat diarrhea due to excess bile acids in the colon

Various miscellaneous antidiarrheals are prescribed to control
diarrhea. This group includes

Codeine is an example.

(accumulation of hard fecal material in the
large intestine) is a relatively common complaint and a major
problem for older adults

Contributing Factors of constipation

Nursing Interventions in antidiarrheals

Patient teaching in antidiarrheals

Nonpharmacologic Measures of Constipation

A “normal” number of bowel movements ranges between _____ per day to ____ per week

are used to eliminate fecal matter.

Laxatives promote a ____ stool, cathartics result in a _____stool with some cramping, and frequently dosage determines whether a drug acts as a laxative or cathartic.

are “harsh” cathartics that cause a watery stool with abdominal cramping

There are four types of laxatives:

Laxatives should be avoided if there is any question that
the patient may have __________

a type of laxative which include salts or saline products, lactulose, and glycerin.

Saline products consist of _________, and a small amount is systemically absorbed.

REMEMBER: Serum electrolytes should be monitored to avoid
electrolyte imbalance in taking Osmotics

REMEMBER: . Hyperosmolar salts pull water into the
colon and increase water in the feces to increase bulk, which
stimulates peristalsis (Osmotics)

cause a semiformed to watery stool according to low or high doses

Saline cathartics are contraindicated for patients with

Osmotic laxatives contain electrolyte salts, including

With PEG, polythylene glycol (a laxative for bowel preparation), however, a large volume of solution, approximately _ to _liters over _ hours, must be ingested.

REMEMBER: Patients may be advised to keep Polyethylene glycol (PEG) ,marketed as GoLYTELY, REFRIGERATED to make it more palatable

The positive aspect of Polyethylene glycol (PEG) marketed as GoLYTELE, that the solution is an isotonic, nonabsorbable osmotic substance that contains sodium salts and potassium chloride; thus it can be used by patients with ______ or _________

another saline laxative that is not absorbed,
draws water into the intestines to form a soft stool. It decreases
the serum ammonia level and is useful in liver diseases, such
as cirrhosis.

acts like lactulose, increasing water in the feces in the large intestine. The bulk that results from the increased water in the feces stimulates peristalsis and defecation.

REMEMBER: Patients who have RENAL INSUFFICIENCY should avoid magnesium salts. Hypermagnesemia can result from continuous use of magnesium salts, causing symptoms such as drowsiness, weakness, paralysis, complete heart block, hypotension, flush, and
respiratory depression

The side effects of lactulose use include flatulence,
diarrhea, abdominal cramps, nausea, and vomiting. Patients
who have diabetes mellitus should avoid lactulose, because it
contains

increase peristalsis by irritating sensory nerve endings in the intestinal mucosa.

Stimulant (contact or irritant) Laxatives types include those containing

is the most frequently used and abused laxative and can be purchased OTC.

REMEMBER: . Bisacodyl and several others of these drugs are used to empty the bowel before diagnostic tests (barium enema).

a harsh laxative (purgative) that acts on the
small bowel and produces a watery stool.

REMEMBER: The action of Castor Oil is quick, within 2 to 6 hours, so the laxative should NOT be taken at bedtime. Castor oil is seldom used to correct constipation. It is used mainly for bowel preparation

REMEMBER: excessive and chronic use of bisacodyl, fluid and
electrolyte (especially potassium and calcium) imbalances are
likely to occur.

REMEMBER: Castor oil should not be used in early pregnancy, because it stimulates uterine contraction. Spontaneous abortion may result. Prolonged use of senna can damage nerves, which may result in loss of intestinal muscular tone

are natural fibrous substances that
promote large, soft stools by absorbing water into the intestine, increasing fecal bulk and peristalsis.

Powdered bulk-forming laxatives, which sometimes come in flavored and sugar-free forms, should be mixed in a glass of water or juice, stirred, drunk immediately, and followed by

This group of laxatives does not cause laxative
dependence and may be used by patients with diverticulosis,
irritable bowel syndrome, and ileostomy and colostomy.

examples of bulk-forming laxatives.

Patients with HYPERCALCEMIA should avoid CALCIUM POLYCARBOPHIL because of the
significant amount of ______ in the drug

Abdominal cramps may occur if the Bulk-forming laxatives are used in ___ form

are a new category of laxatives used to treat idiopathic constipation in adults.

This drug activates chloride channels in the lining of the small intestine, leading to an increase in intestinal fluid secretion and motility

Lubiprostone is contraindicated for patients
with a history of

REMEMBER: Adverse effects of lubiprostone include nausea, which seems to be dose-dependent,
diarrhea, headache, abdominal distention, and flatulence

are lubricants and stool softeners (surface-acting
or wetting drugs) used to prevent constipation. These drugs
decrease straining during defecation.

Lubricants such as _______ increase water retention in the stool.

Mineral oil absorbs essential fat-soluble vitamins A, D, E, and K. Some of the minerals can be absorbed into the lymphatic system

work by lowering surface tension and promoting water accumulation in the intestine and stool. They
are frequently prescribed for patients after myocardial infarction or surgery. They are also given before administration of
other laxatives in treating fecal impaction.

examples of stool softeners.

This laxative is not indicated for children, older
adults, or patients with debilitating diseases, because they
might aspirate the _______, resulting in lipid pneumonia.

. Contraindications to the use of laxatives include

Patient teaching on laxatives: stimulants