DRUGS ACTING ON THE GASTROINTESTINAL SYSTEM Flashcards
Drugs Affecting GI secretions
histamie-2 antagonists
antacids
proton pump inhibitors
GI protectant
prostaglandin
miscellaneous agents
Drugs affecting GI motility
laxatives
antidiarrheals
antiemetics
Miscellaneous drugs to treat self-poisoning
activated charcoal
these agents prevent the stimulation of the secretory cells by blocking
histamine receptors at the parietal cells of the stomach. This action ultimately
results to a decrease in the secretion of gastric acid as well as a decrease in the
production of pepsin.
Histamine 2 Antagonists / Histamine-Blocking Agents
these agents are used as prophylaxis in susceptible patients (e.g.
those who are critically ill and high risk to develop stress-induced ulcer); as
short-term treatment of active ulcer; treatment of pathologic hypersecretory
conditions (e.g. Zolliner-Ellison Syndrome), GERD; relief of relief symptoms of
heartburn, sour stomach (OTC preparations)
Histamine 2 Antagonists / Histamine-Blocking Agents
Adverse effects of Histamine-2 Antagonists
diarrhea or constipation
headache
confusion
dizziness
impotence
gynecomastia
arrhythmias
hypotension
rashes
increased level of histamin-2 antagonists
warfarin
phenytoin
chloroquine
theophylline
lidocaine
nifedipine
these are inorganic, alkaline agents that act as stomach acid neutralizers
by direct chemical reaction resulting to increase pH of stomach contents.
Antacids
The primary goal of antacid therapy is the relief of pain through:
- neutralization of stomach acid
- improved resistance of stomach lining
- increased tone of the lower esophageal sphincter
- inhibition of pepsin’s protein-digesting ability
for the symptomatic relief of upset stomach associated with
hyperacidity, as well as the hyperacidity associated with peptic ulcer, gastritis,
peptic esophagitis, gastric hyperacidity, and hiatal hernia
antacids
duration of action of antacids
30-60 minutes
increased level of antacids
quinidine
amphetamines
dicumarol
these agents suppress gastric acid secretion by inhibiting the hydrogen–
potassium adenosine triphosphatase enzyme system that is needed in the final
step of acid production
proton pump inhibitors
these agents are used in the treatment of ulcers, GERD, erosive
esophagitis, hypersecretory conditions, H. pylori infection (as adjunct therapy)
proton pump inhibitors
safety and efficacy of these agents have not been established in patients
younger than 18 years old except,
lansoprazole
– increased cardiovascular effects when it interacts with proton pump inhibitors
clopidogrel
– decreased level of these drugs when it interacts with proton pump inhibitors
ketoconazole
theophylline
– increased serum levels of these
drugs when it interacts with proton pump inhibitor
benzodiazepines
phenytoin
warfarin
– impaired absorption of this drug when it interacts with proton pump inhibitor
sucralfate
Proton pump inhibitors are taken before or after meals?
before meals
These are cathartic agents used to increase GI motility and promote bowel evacuation through several mechanisms
Laxatives
they directly stimulate the sensory nerve endings in the intestinal wall causing chemical irritation of the intestinal mucosa. Most exert local effects on the GIT and are not absorbed systemically
Chemical Stimulants
rapid-acting laxatives that absorb fluid in the intestinal contents which increases fecal bulk and stimulates peristalsis; generally not absorbed in the system
Bulk stimulants/ mechanical stimulants
works by exerting a detergent action on the surface of the intestinal
bolus making the stools softer (docusate), by forming a slippery coat on the
intestinal bolus (mineral oil), or by exerting a hyperosmolar pull (glycerin).
These agents are not absorbed systemically
Lubricants
