Lecture 19: GI Pharm II Flashcards
Four causes of gastroparesis
Diabetes, thyroid disorder, CT disorders (scleroderma), pregnancy
Classes of anti-emetics
Central muscarinic, dopaminergic, histaminergic, serotinergic (5-HT3)
Phenothiazines: mechanism and AEs, example
Block D2 receptors in CTZ; PD-like effects, chlorpromazine
Buytrophenones: mechanism, and AEs, example
Block D2 receptors; PD-like effects, halperidol
5-HT3 antagonists: mechanism, side effect, examples
Inhibit 5-HT at 5-HT3 receptor in CTZ and SI; causes constipation, ondansetron (and other setrons, note that ondansetron is a majorly used anti-emetic)
Anti-diarrheals: examples and goal of therapy
Loperamide, diphenoxylate w/ atropine, codeine; reduce small bowel TRANSIT TIME to allow for proper absorption
Octreotide: mechanism, use
Somatostain analogue which reduces secretion; most useful in inhibiting release of hormones due to neuroendocrine tumor
Clonidine: mechanism, use, SEs
Alpha-2 adrenergic stimulation increases electrolyte absorption/inhibits secretion, most commonly used during narcotic withdrawal; causes hypotension
What cells release 5-HT in the gut? Effects of 5-HT? Drug receptor targets?
Enterochromaffin cells; stimulates motility and secretion; 5-HT3/5-HT4
Alosetron: mechanism, use, AE
Antagonism of 5-HT3 for treatment of IBS diarrhea; rare cause of ischemic colitis
Constipation: what do we want to do? Describe ion transport.
Increase Cl- secretion; basolaterally via Na/K/2Cl, exits apically via CFTR, and type 2 Cl- channel (CIC-2)
Cl secretion is increased/decreased by activation of cAMP, cGMP, Ca2+
Increased
Lubiprostone: mechanism
PGE derivate selective on type 2 Cl- channel (CIC-2), enhancing Cl- secretion
Linactolide: mechanism
Agonist of GC –> cGMP –> CFTR –> Cl- secretion
