Pharmacology of Prokinetics, Acid-Peptic Disorders, and Antiemetics (Quiz) Flashcards
what is gastroparesis
- failure of the stomach to empty properly
what does motilin do
- stimulate motility
what does dopamine do for motility
how
- inhibits motility
- inhibitory presynaptic dopamine receptor (D2)
what does acetylcholine do for motility
- stimulates motility
MOA of Metoclopramide
- inhibition of dopamine D2 receptor
- increase contraction and motility
Toxicities of Metoclopramide
short or long term use
- acute dystonia - short term
- tardive dyskinesia - long term
- hyperprolactinemia
- anxiety, restlessness, depression
what are acute dystonia and tardive dyskinesia known as
- extrapyramidal symptoms (EPS)
how EPS’s caused
important brain parts involved
- inhibition of central dopamine pathway that regulates skeletal muscle movement
- substantia nigra
- dorsal striatum
how does Metoclopramide cause hyperprolactinemia
- inhibits central dopamine pathway that inhibits release of prolactin
- therefore excessive prolactin secreted
Erythromycin MOA
- motilin receptor agonists
side effect of Erythromycin
- GI distress
pharmacokinetics issues with Erythromycin
- tachyphylaxis (desensitization) after 10-14 days
what drug do you use if metoclopramide fails
- erythromycin
MOA of Neostigmine
- indirect acting cholinergic agonist
- inhibits acetylcholinesterase and increases amount of acetylcholine at synapse
toxicities of Neostigmine
- pro parasympathetic effects
- excessive saliva production
- decreased CO
- bradycardia
what is the antidote to Neostigmine
- atropine
role of prostaglandin E2
- inhibits gastric acid secretion
MOA of Sucralfate
- polymerizes at low pH of stomach
- negatively charged so binds positively charged proteins in stomach ulcer
- forms a barrier
types of antacids
- NaHCO3
- CaCO3
- Al(OH)3
- Mg(OH)2
MOA of antacids
- directly neutralize stomach acid
toxicity of NaHCO3
- metabolic alkalosis
toxicity of Mg(OH)2 and Al(OH)3
how do we solve this
- diarrhea
- constipation
- combine the two to off-set each other’s toxicities
toxicity of antacids
how
- hypophosphatemia
- molecules are insoluble and prevents PO4 absorption
which are the antihistamines
- Ranitidine
- Famotidine
- Cimetidine
MOA of Antihistamines
- competitive, reversible inhibitors of H2 receptor in parietal cells
can acid-peptic antihistamines significantly cross the blood brain barrier
- no
pharmacodynamics issue with Antihistamines
- other pathways may compensate for blockage and build up tolerance
important toxicity of Cimetidine
which drugs
what’s the exception to the rule
- drug interactions due to inhibition of CYP enzymes
- will reduce their clearance
- warfarin
- anti-epileptics
- theophylline
- clopidogrel - doesn’t get activated
- oral contraceptives
importance of theophylline
- low therapeutic index
proton pump inhibitor drugs
- omeprazole
- esomeprazole
- lansoprazole
- pantoprazole
- rabeprazole
MOA of PPIs
- irreversible non competitive antagonist of H+/K+ pump
toxicities of PPIs
- C. diff infection
- hypomagnesia
- vitamin B12 malabsorption
- AIN
pharmacokinetics issues with PPIs
- pH trapping drives them into secretory canaliculus
MOA of Misoprostol
- prostaglandins E2 analog
- inhibits gastric H+ secretion
toxicities of Misoprostsal
- promotes abortion of fetus
what are some neurotransmitters associated with signals that affect vomiting
- dopamine
- serotonin
- acetylcholine
- neurokinin
MOA of Ondansetron
what’s it used for
- serotonin antagonist
- anti-emetic
Toxicities of Odansetron
- prolonged QT interval
MOA of Prochlorperazine and promethazine
what are they used for
- D2 receptor antagonists
- anti-emetic
toxicities of Prochlorperazine and promethazine
- acute dystonia
- tardive dyskinesia
- prolonged QT
for what conditions do you use sucralfate
- GERD (pregnancy)
for what conditions to you use antacids
- GERD
for what conditions do you use antihistamines
- GERD
- peptic ulcer disease
for what conditions do we use PPIs
- GERD
- peptic ulcer disease
- Zollinger-Ellison syndrome
- NSAID associated ulcers
- H. pylori eradication
for what conditions do we use misoprostol
- NSAID associated ulcers
