GNUR 294 FINAL EXAM REVIEW (M19-22)
MODULE 19
PHARMACOTHERAPY OF GI DISORDERS
Upper GI
• Upper GI disorders – most prevalent in US
o Requires the most pharmacologic therapy
• Upper GI tract consists of the stomach and the esophagus
o Anything below the duodenum is considered lower GI...
GNUR 294 FINAL EXAM REVIEW (M19-22)
MODULE 19
PHARMACOTHERAPY OF GI DISORDERS
Upper GI
Upper GI disorders – most prevalent in US
oRequires the most pharmacologic therapy
Upper GI tract consists of the stomach and the esophagus
oAnything below the duodenum is considered lower GI tract – we don’t commonly administer drugs that effect lower GI tract in US
Disorders of upper GI tract include
oPeptic ulcer disease (PUD)
oGastroesophageal reflux disease (GERD)
Mechanism of action of Anti-ulcer drugs
Proton pump inhibitors (PPI) – blocks acid production and heals
Histamine-2 receptor blockers – reduces acid production
Antacids – neutralizes stomach acid
Proton pump inhibitors
omeprazole
Route: PO, IV
Onset: 0.5-3.5 hr – takes weeks to be completely effective
Duration of action: 3-4 days
Indications:
PUD
GERD
Heartburn
H. pylori (combined with antibiotics)
Mechanism of action: binds irreversibly with H, K, ATPase and inhibits acid secretion
Adverse effects:
HA
N/V
Rash
AB pain
Contraindications:
Hypersensitivity
Caution: hepatic impairment – if taking OTC and not as directed = 50% risk of developing
renal failure
Pregnancy: Category C
Omeprazole is now sold OTC because it was so well tolerated and safe when taken as directed
Omeprazole dose not prevent the reflux of gastric contents it decreases acid amount that is causing pain and toxicity to those tissues Needs to be given 30 min before meals – otherwise pump has already started to release HCl and medication will be ineffective, functions based on food coming into stomach, pump is triggered by food being propelled through esophagus to stomach pumps HCl
Histamine-2 receptor antagonists
ranitidine
*Histamine-1 receptors – triggered by mast cells by immune system response or allergic response
*Histamine-2 receptors – only in the stomach, blocks parietal cells (these cells stimulate acid production), has nothing to do with the immune system
Route: PO, IV
Onset: 30-60 min
Duration of action: 6-12 hr
Indications:
PUD
GERD
Heartburn
Mechanism of action:
Blocks H2 receptors on parietal cells and decreases acid production
Adverse effects:
Blood dyscrasias (rare)
Confusion (elderly)
Gynecomastia, impotence, decreased libido (if not taken as directed)
Contraindications:
Hypersensitivity
Acute porphyria – abnormality in RBC metabolism which results in pt having purple urine and stool
Pregnancy: Category B – site of uterus can push up against stomach and increase symptoms of GERD and heartburn
Antacids
OTC medications that are initially tried by pt when experiencing symptoms of PUD or GERD
Neutralizes gastric acid
Stimulates prostaglandins to increase gastric mucosal lining
Increases LES tone
Duration – 2 hr, needs to be taken frequently
Adverse effects if taken in excess:
oSevere constipation from excess aluminum and calcium
oFluid retention from excess sodium significant complications in HTN, HF
oVentricular dysrhythmias from excess magnesium
oMetabolic alkalosis from excess bicarbonate
Drug-drug interactions – binds with other drugs, should be taken 1hr before or after other drugs H. pylori treatment
Minimum of 2 antibiotics prescribed to decrease risk for developing resistance
Omeprazole, clarithromycin, amoxicillin – most common and most effective
PPI, clarithromycin, metronidazole
PPI, bismuth subsalicylate, metronidazole, tetracycline
Miscellaneous
Sucralfate – helps increase mucosal lining, bicarbonate and prostaglandin release neutralizes stomach acid and protects stomach
Bismuth compounds – stimulates mucosal production and prostaglandins can cause black stools (common side effect)
Misoprostol – synthetic prostaglandin, misoprostol is also a drug used to terminate pregnancies, WILL cause miscarriage = Category X Metoclopramide – blocks nausea triggering zone in brain and used to increase peristalsis
= decreases acid in stomach
Anticholinergics – helpful but has adverse systemic effects
Pharmacotherapy of N/V
Antiemetic – serotonin (5-HT3) receptor antagonist
ondansetron
Most commonly prescribed antiemetic
Blocks stimulation of medulla (vomiting center)
The medulla gets triggered by various stimuli both inside and outside of the body
The most common pt to experience nausea = cancer pt receiving chemo
oComplications of N/V = fluid and electrolyte imbalance
Emetics are for stimulating the vomiting center – used to induce vomiting
MODULE 20
PHARMACOTHERAPY OF ALZHEIMER’S AND SEIZURE
Alzheimer’s Disease
Most common cause of dementia – 4th leading cause of death in US
AD is a neurodegenerative disease that leads to chronic loss of function
Etiology is unknown but could be from chronic inflammation, genetic, environment
AD is R/T neurofibrillary changes and Ach deficiency – Ach is a neurotransmitter that helps with neuron function
Drugs do not cure AD – only slows the progression
NMDA receptor blocker
memantine
Newest category for AD
Prevents glutamate from causing excitatory actions – slows nerve degeneration
Contraindicated in renal failure or renal insufficiency
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