GI deck 2 Flashcards
antihistamines use with caution in
elderly - anticholinergic properties
Antihistamine ADR
Drowsiness
Anticholinergic effects of dry mouth, blurred vision, and urinary retention
Phenothiazines ADR
Drowsiness
EPS, such as dystonia, akathisia, and tardive dyskinesia
Promethazine: fatal respiratory depression in children younger than 2 years of age
Scopolamine ADR
Dry mouth
Withdrawal symptoms
Cnnibinoid dronabionl ADR
Euphoria, depression, dizziness, paranoid thoughts, somnolence, and abnormal thoughts
Cardiac effects: palpitations, tachycardia, and hypotension
Seizure and seizure-like activity have been reported
5-HT3 receptor antagonists - ADR
Constipation, headache, fatigue, dizziness, and diarrhea
Rare cases of tachycardia, bradycardia, hypotension, and heart rate-corrected QT interval prolongation
Phenothiazines and lithium: may increase
eps
Phenothiazines and lithium: may mask
LITHIUM TOXICITY
Nausea and vomiting - Drugs used
5-HT3 receptor antagonists
Phenothiazines
Phenothiazines are not used in
children
Dronabinol is only for use in
in chemotherapy-associated nausea and vomiting, and for appetite stimulation.
Motion sickness drug used
anti-histamines
vomiting caused by gastroparesis drug used
prokinetic drug
Motion Sickness drug is most effective when given
prophylactically
Scopolamine patch – very effective but
apply approx. 12-24 hours before motion sickness triggering event. This is RX only
Other use for scopolamine can be to prevent
nausea from anesthesia apply 12-24 hours before surgery when pts have severe N/V from anesthesia.
Antihistamines are other main group that can help motion sickness- examples
examples Bonine (meclizine), Dramamine (dimenhydrinate)
Histamine 2 Receptor Antagonists inhibit
acid secretion gastric parietal cells blocks histamine at histamine 2 receptors
Histamine 2 Receptor Antagonists reduce acid by
35 - 50 %
Histamine 2 Receptor Antagonists examples
cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid)
H2RA caution in
renal and liver impairment, can have CNS adverse reactions – although not common could be serious but is reversible
Famotidine approved for
infant and children as young as neonates, ranitidine approved for children 1 month to 16 years
Cimetidine has the most
interactions with foods/drugs
Indications/Clinical use: GERD, Heartburn, PUD - can be used as maintenance therapy after PPI therapy, Ok for longer term use
What interferes with absorption of H2RA
Smoking does interfere with absorption of this drug
Prokinetic agents stimulate
motility of the GI tract without stimulating gastric, biliary, or pancreatic secretions
only drug in prokinetic class
metoclopramide
Prokinetic pharmcodynamics
Metoclopramide stimulates motility in the upper GI tract.
Metoclopramide also has some actions similar to the phenothiazines and dopamine antagonists.
Metoclopramide (reglin) also has some actions
similar to the phenothiazines and dopamine antagonists.
Metoclopramide has a Black Box warning
due to risk of developing tardive dyskinesia
Prokinetics are contraindicated in gastrointestinal
hemorrhage, mechanical obstruction, new surgery on the GI tract, or perforation.
Prokinetic use cautiously in
hemorrhage, mechanical obstruction, new surgery on the GI tract, or perforation.
Prokinetic ADR
Tardive dyskinesia Depression, dizziness Diarrhea Hypoglycemia in patients with diabetes Rare: galactorrhea, amenorrhea, gynecomastia, impotence secondary to hyperprolactinemia
Prokinetics Drugs - Interactions
Additive CNS depression occurs when used with other CNS depressants.
Increased risk of EPS occurs with other drugs that have the potential for EPS.
Drugs with anticholinergic effects reverse the action of metoclopramide.
Prokinetic drug clinical use
GERD, diabetic gastroparesis
Monitor – renal function, new-onset movement disorder, depression or suicidal ideation
proton pump inhibitors suppress
gastric acid secretion, can reduce secretion of acid as much as 90%
PPI are all acid-
are acid-labile, most formulated as enteric coated capsules
PPI are overall safe but
safe drug, use with caution in hepatic dysfunction and elderly – no dosage adjustments are recommended
PPI are safe in what
pregnancy but always weigh risks benefits
PPI should only be used
short term
PPI long term use is not advised due to
to PPIs causing nutrient deficiencies with iron, B12 and calcium absorption interference. Long term can lead to increased risk for fracture.
PPI long term use increases
risk for chronic kidney disease
PPI long term use have increased risk of
infection from C diff, Salmonella, Campylobacter as the decrease in stomach acid decreases the bodies natural defenses against antimicrobial
PPI long term use also shows intrease risk of
gastric cancers because of chronic atrophic gastritis
All PPIs may interfere with
oral administered drugs – see drug interactions table in text
PPI clincal indications
Duodenal and gastric ulcers, GERD
PPI some times are used long term but
rarely and usually only with hypersecratory conditions such as Zollinger-Ellison syndrome
Average recommended treatment duration for PPI
4 to 8 weeks
