Final Exam Flashcards
What types of drugs affect gastric secretion?
- Antacids (weak base to neutralize excess acid in stomach)
- H2 histamine receptor antagonists (stop stomach from producing acid)
- Proton pump inhibitors (stop stomach from producing acid)
- Protectants (protect esophageal lining)
What types of drugs increase GI motility?
- Laxatives
- Prokinetic drugs
What types of drugs reduce GI motility?
- Antidiarrheals
- Anti-emetics
Describe the events that lead to gastric acid secretion starting with the intake of dietary peptides
- dietary peptides act on G cells
- G cells produce gastrin
- Gastrin enters bloodstream
- Gastrin acts on ECL cells
- ECL cell signaling cascade releases histamine
- Histamine binds to H2 receptors on parietal cells
What type of cell produces histamine in the GI tract?
ECL (enterochromaffin-like) cells
Which antacids have high neutralizing capacity?
NaHCO3
Al(OH)3
Mg(OH)2
Which antacid has moderate neutralizing capacity?
CaCO3
What is one adverse effect of CaCO3?
milk-alkali syndrome
What is one adverse effect of NaHCO3?
systemic alkalosis
What is one adverse effect of Al(OH)3?
constipation
What is one adverse effect of Mg(OH)2?
diarrhea
Why don’t histamine receptor antagonists cause complete deactivation of parietal cells?
Parietal cells are activated through other mechanisms aside from histamine, including CNS activation from acetylcholine and from gastrin
What are the 2nd generation H2 receptor antagonists?
Ranitidine (Zantac)
Nizatidine (Axid)
Famotidine (Pepcid)
What are the characteristics of 2nd generation H2 receptors antagonists?
-longer half-life (HS vs. BID dosing)
-fewer effects on CYP450 system
-greater potency
-absorbed quickly to reduce parietal cell function
What is the mechanism of action of proton pump inhibitors?
They irreversibly bind to the H+/K+ ATPase pump
What is the difference between omeprazole and esomeprazole?
Omeprazole: racemic mixture, less potent
Esomeprazole: S-enantiomer, more potent
Proton pump inhibitors are substituted ______________
Benzimidazoles
Why do proton pump inhibitors have slow onset?
They must be absorbed in the small intestine, circulate, and then be taken up by the parietal cells
What activates the prodrug form of a PPI?
The acidic pH in the parietal cell
PPIs have a ______ plasma life but _____ duration action
short, long
What are the 5 risk factors for GERD?
- Obesity
- Tobacco smoking
- Genetic predisposition
- Pregnancy
- Delayed gastric emptying
What are the 5 characteristics of GERD pathophysiology?
- Abnormal esophageal clearance
- Lower LES pressure (LES = lower esophageal sphincter)
- Decrease in esophageal mucosal resistance
- Delayed gastric emptying + increase intra-abdominal pressure
- Acid pocket formation
What medications are a direct irritant to esophageal mucosa?
- aspirin + NSAIDS
- Bisphosphonates
- Iron
- Quinidine
- Potassium chloride
What is the mechanism of action of H2RAs?
Reversible inhibition of histamine receptors on parietal cells
Name two mucosal protective agents
sucralfate (Carafate)
misoprostol (Cytotec)
What is sucralfate’s mechanism of action?
aluminum hydroxide complex of sucrose polymerizes to form a kind of gel which creates a protective barrier at ulcer site
acidic pH activates complex
What is misoprostol’s mechanism of action?
semi-synthetic prostaglandin derivative that enhances mucus and bicarbonate secretion and reduces acid secretion
Name the four types of laxatives and one example for each
- Bulk-forming - Psyllium (Metamucil)
- Osmotic - PEG 3350 (MiraLax)
- Stool softener - Docusate (Colace)
- Stimulant - Bisacodyl (Dulcolax)
Name 7 prokinetic drugs (not including opioid-receptor antagonists)
- Metoclopramide (Reglan)
- Prucalopride (Motegrity)
- Tegaserod (Zelnorm)
- Lubiprostone (Amitiza)
- Linaclotide (Linzess)
- Plecanatide (Trulance)
- Tenapanor (Ibsrela)
What is metoclopramide’s mechanism of action?
D2 dopamine receptor antagonist in the myenteric plexus which leads to acetylcholine release
(the myenteric plexus is responsible for peristalsis which can be stimulated by ACh)
Describe the mechanism of action of prucalopride and tegaserod
5HT4 serotonin receptor agonist that activates Gs pathway -> increased cAMP, PKA activation and release of acetylcholine
Which prokinetic drugs are chloride channel activators?
- Lubiprostone (stimulates CIC-2 activator in small intestine)
- Linaclotide and Plecanatide (peptide activator of guanylate cyclase C)
Which prokinetic drug inhibits the sodium/hydrogen exchanger (NHE3)?
Tenapanor
*increased Na+ in the gut leads to increased water in the gut accelerating transit of intestinal contents
Which anti-emetics antagonize 5-HT3 receptors?
Ondansetron (Zofran)
Granisetron (Kytril)
Dolasetron
Palonosetron
Which anti-emetics antagonize NK1 receptors?
Aprepitant
Netupitant
Rolapitant
Which anti-emetics act as antihistamines and anticholinergics?
Dimenhydrinate (Dramamine)
Meclizine (Antivert)
Scopolamine
Name four D2 dopamine receptor antagonists that act as antipsychotics and anti-emetics
- Metoclopramide (Reglan)
- Prochlorperazine (Compazine)
- Promethazine (Phenergan)
- Droperidol (Inapsine)
What is the preferred regimen for H. pylori treatment?
bismuth salt (subsalicylate, subcitrate)
metronidazole
tetracycline
PPI BID
x10-14 days
What does the levofloxacin triple therapy consist of?
- Levofloxacin daily
- Amoxicillin BID
- PPI BID
What does the rifabutin triple therapy consist of?
- omeprazole
- amoxicillin
- rifabutin
q8h x14 days
What is one counseling point for metronidazole?
avoid alcohol due to disulfiram-like reaction (nausea and vomiting)
What is an adverse effect of penicillins?
GI upset, take with food
What are three adverse effects of fluoroquinolones?
tendon rupture
mental status change
QTc prolongation
What is an adverse effect of tetracyclines?
photosensitivity
What are three adverse effects of macrolides?
GI upset
photosensitivity
QTc prolongation
What are the two key questions for choosing the H. pylori regimen?
- Is there a penicillin allergy?
- Does the patient have previous macrolide exposure for any reason?
What are the options if H. pylori treatment doesn’t work?
- Switch antibiotics (not used in the first regimen)
- Salvage regimens
- Extend duration of therapy to 14 days
- Penicillin skin test if PCN allergy listed
What are the three main causes of peptic ulcer disease?
- H. pylori
- NSAIDS
- Stress
Which causes of ulcer usually result in a stomach ulcer?
NSAIDS, stress
Which cause of ulcer usually results in a duodenal ulcer?
H. pylori
Which cause of ulcer creates the deepest ulcer?
NSAIDS
In which type of ulcer is pain relieved by food?
Duodenal ulcer
In which type of ulcer is pain worsened by food?
Stomach ulcer
Is misoprostol used for treatment or prevention of NSAID-induced PUD?
prevention (prophylaxis)
Is sucralfate used for treatment or prevention of NSAID-induced PUD?
treatment
For which type of ulcer are H2RAs used for prevention?
duodenal ulcers
What 5 processes occur in the body in a well-fed state?
- insulin release
- glycolysis
- glycogen synthesis
- catabolism of amino acids
- fatty acid synthesis
What 3 processes occur in the body in an early fasting state?
- glucagon release
- glycogen breakdown
- gluconeogenesis (cori and alanine cycle)
(no catabolism of amino acids)
What 5 processes occur in the body in a fasting state?
- Glucagon release
- Gluconeogenesis
- Lipolysis (adipose tissue)
- Fatty acid oxidation
- Ketogenesis (liver)
Define marasmus
Inadequate intake of both protein and energy
Define kwashiorkor
Inadequate intake of protein with adequate energy intake
Define pellagra
severe deficiency of niacin (B3)
Define beriberi
severe deficiency of thiamin (B1)
What process is inhibiting by a folic acid (B9) deficiency?
DNA synthesis
infants have _______ heart rates and respiratory rates, but _______ blood pressure
high, low
postmenstrual age =
gestational age + postnatal age
corrected age =
postnatal (actual) age - weeks born early
oliguria is defined as….
< 0.5mL urine/kg/hour
anuria is defined as….
0 mL urine/kg/hour
eGFR (mL/min/1.73m^2) =
0.413(height in cm/SCr)
