PH CM2 Cu 9 - Drugs Affecting Git
PH CM2 Cu 9 - Drugs Affecting Git
PH CM2 Cu 9 - Drugs Affecting Git
Cognitive:
Gastrin – hormone secreted by the gastric cells that stimulate production of gastric juice
Histamine 2 receptors – receptors in the parietal cells for histamine 2
Local gastric reflexes – nervous plexuses in the walls of the GIT that generate impulses
throughout the GIT causing peristaltic movement
Nervous plexus – network of nerves innervates by the autonomic nervous system.
Parasympathetic stimulates, while sympathetic inhibits them
Peristalsis – mixing and propulsive contraction of the smooth muscles in the
gastrointestinal wall that promote GI movement
Putrifaction – a process by which bacteria in the colon act on fecal material producing
gasses
Vomiting – complex reflex reaction to various stimuli causing regurgitation of ingested food
REQUIRED READING
Karch, A. M. (2019). Focus on nursing pharmacology. Lippincott Williams & Wilkins.
The GIT is innervated by the autonomic nervous system. Parasympathetic stimulates while
Sympathetic inhibits GI movement and secretion. Local reflexes made by nervous plexuses along the
wall of the GIT also participate in normal peristaltic movement. Gastroenteric reflex happens when
stretching of the stomach will cause impulses going to the intestine and stimulate it to produce its
secretion and create peristalsis and stimulate gastric emptying. Gastrocolic reflex happens when the
presence of food stretches the stomach, the nervous plexus will send signal to the colon to cause
peristalsis. Duodenal – colic reflex also happens when chyme passes the duodenum will cause
stretching of the wall thereby sending impulses to the colon to create peristaltic waves and stimulate
defecation.
The interplay of autonomic and local reflexes helps in the release of gastric and intestinal secretions
and peristaltic movement.
There are two centrally mediated reflexes that are important in the function of the GIT. The swallowing
reflex and vomiting.
Act of swallowing is initially voluntary. A person should put the bolus of food at the back of the tongue
and pressed it against your palate, this will require voluntary muscles. The pharyngeal and esophageal
phases are involuntary and made by peristaltic movement of their wall.
Vomiting happens when the chemoreceptor trigger zone (CTZ) in the medulla, anything that stimulate
CTZ will cause nausea and vomiting. Most common stimuli to induce vomiting include:
1. Tactile stimulation at the back of the throat
2. Excessive gastric distention
3. Any inflammation in the abdominal region
4. Any obstruction in the abdominal region
5. Increased intracranial pressure
6. Certain drugs like anticancer agents
These drugs are used for treatment of gastroesophageal reflux disease, gastritis and peptic ulcer
disease (PUD). The common etiology for these disorders is the increase corrosive effects of
hydrochloric acid in the mucosal ling of the stomach and small intestines causing inflammation and
erosions.
Histamine 2 Receptor antagonist - block the receptors for histamine 2 in the parietal cells
to stop release of hydrochloric acid from the parietal cells.
o Pharmacokinetics: readily absorbed after oral administration, liver metabolized
the drug and excreted in the urine.
o Contraindications and Cautions: Contraindicated to clients with known allergy to
the drugs. Pregnancy and lactation
o Adverse effects: drugs may cause diarrhea or constipation, dizziness, insomnia,
gynecomastia and impotence
o Drug – Drug interactions: these drugs may slow down metabolism of some drugs
thereby increasing serum levels and toxicity. This includes anticoagulants, beta
blockers, theophylline, nifedipine, phenytoin and alcohol
o Examples: Ranitidine, Cimetidine, Famotidine
Nursing considerations
o Should be given before meals or at bedtime
o Monitor hepatic toxicity
o Monitor for potential drug – drug interaction
o Assess for GI adverse effects
o Provide Health teaching as to the name of the drug, prescribed dosage, action and
adverse effects to enhance patient’s knowledge and promote good compliance
Anti – peptic drug – these drugs protect the lining of the GIT to prevent further
irritation of mucosa
Pharmacokinetics: rapidly absorbed, metabolized in the liver and excreted in
the feces. Drugs pass the placenta and breastmilk
Contraindication: should not be given to client with allergy to the drug. It
should not be given to client undergoing dialysis for renal failure because of
buildup aluminum if antacid contain aluminum.
Adverse Effects: Constipation, diarrhea,indigestion, gastric discomfort,
dizziness, sleepiness and vertigo
Examples: Sucralfate
Nursing considerations:
o Administer 1 hour before meals
o Monitor for GI adverse effects
o If antacids will be administered as well, antacids should be given in between doses of
sucralfate.
o If CNS effects are seen, provide safety
o Provide frequent mouth care and sugarless lozenges
o Give health teaching about the drug, its action and adverse effects to enhance patient’s
knowledge and compliance
Constipation and diarrhea are most common causes of GI disturbances. The most important
management is fluid administration for both condition. Increase fluid intake in constipation will
soften the stool in the colon, and oral rehydration solution will prevent dehydration from
diarrhea.
Classifications of laxatives
1. Chemical laxative – directly stimulate the GIT to increase peristaltic movement and
promote defecation
o Examples: Bisacodyl, Cascara, Senna
2. Bulk laxative – increase fluid in the lumen to stimulate local reflexes and promote
defecation
o Examples: Lactulose, Psyllium
3. Lubricant laxative – soften the stool
o Examples: Docusate , Glycerine
Pharmacokinetics: these drugs are minimally absorbed and exert their effect in the
GIT and excreted in the feces
Contraindications: Not given to clients with abdominal disorders like appendicitis,
diverticulitis and ulcerative colitis
Adverse Effects: primary adverse effect is diarrhea, fluid and electrolyte disturbances
and acid – base imbalances
Nursing considerations:
o Laxatives are given if independent interventions are not effective
o Monitor for possible diarrhea as adverse effects
o Monitor for fluid and electrolyte imbalances
o Assess for signs of acid – base imbalances
o Monitor vital signs
o Provide comfort measures
o Health teaching on the drug name, prescribed dosage, effects, possible adverse
reactions to enhanced client’s knowledge and promote good compliance
Locally acting anti emetic drugs will block stimulation of the CTZ from it source. Centrally acting anti
emetic would block the receptors in the CTZ or the nerves in the CNS that stimulate the CTZ.
Contraindications: Clients with allergy to the drugs should not receive it. Clients with CNS depression
may worsen their conditions. Caution is used to clients who are taking CNS depressants
Adverse effect: CNs effects, drowsiness, weakness, headache, tremor, autonomic effects and
photosensitivity is seen in some patients
Nursing interventions:
o Monitor response of the client to the drug
o Provide safety if CNS effects occur
o Provide comfort measure including mouth care
o Provide adequate health teaching about the dug to increase client’s knowledge and
good compliance
Kee, Joyce Le Fuer and Hayer, Evelyn R., Pharmacology: A Nursing Process Approach, 5th Edition,
2006, by Elsevier (Singapore) PTE LTD
Lilley, Linda lane & Harrington, Scott, Pharmacology and the Nursing Process, 5th Edition, by Elsevier
(Singapore) PTE LTD
Make a drug study on the individual drugs discussed in this course unit. Write them in an ½
index card and compile them.
Search new 2 drugs for each classification of GIT drugs not discussed in this course unit
and include them in the drug study.
DRUG STUDY
DRUG DOSAGE THERAPEUTIC ADVERSE CONTRAINDICATION NURSING
ACTION EFFECTS CONSIDERATIONS