Laxatives, anti diarrheals, and anti-emetics Flashcards
MOA of Metamucil
- dietary fiber/bulk forming laxative
2. hydrophilic muciloid that forms gelatinous mass when mixed w/ water
ADE of metamucil
allergic rxn, flatulence, borborygmi, intestinal obstruction. May inhibit coumarin absorption
MOA of Docusates/colace
anionic surfactant laxatives
- weakly active, stool softener to reduce the strain of defecation.
- has no effect on intestinal peristalsis
ADE and VI for docusates/colace
- NOT for use during ab pain, N/V
- can irritate intestinal mucosa and increase intestinal absorption of other drugs
MOA of castor oil
Rapid acting and effective anionic surfactant laxatives. Produces catharsis - complete evacuation of bowel. stimulates intestinal peristalsis
ADE of castor oil
colic, dehydration, electroylty imbalance w/ overdose.
- can cause uterine contraction in pregnant
MOA of Dulcolax
- stimulant laxative - most potent class of laxatives
2. prodrug converted by enteric bacteria into desacetyl active form.
ADE and CI for dulcolax
- overdose causes excessive fluid/electrolyte loss, intestinal enterocyte damage leading to colonic inflammatory response
MOA of Senna/cascara
natural derivatives of plants. More gentle than synthethics. Act by promoting colonic motility.
- part of stimulant laxative class
ADE fo senna/cascara
large doses can cause ab pain, nephritis, melanotic pigmentation of colonic muscoa, abnormal urine coloration
MOA of lactulose
osmotic effect b/c nondigestible synthetic sugar.
Fecal acidifier, traps ammonia in stool
MOA of lubiprostone
Activates Cl channels to increase intenstinal fluid secretion and motility and alleivates the symptoms associated w/ chronic idiopathic constipation (IBS)
General side effects of laxatives
- overuse leads to constipation that requires several days to accumulate bulk
- lag in defecation is interpreted as continued constipation
- takes more and cycle starts
- if continued bowel becomes unresponsive
MOA of loperamide
interacts w/ opioid receptors and binds to and inhibits Ca binding protein calmodulin. Anti-diarrheal agent
effect of opiates on GIT
- decrease salivary, gastric and intestinal secretions
- decrease motility of stomach and intestines
- increase muscle tone
- increase tone of intestinal sphincters and EAS to reduce urgency
- anti-spasmodics and decrease cramps
MOA of scopolamine
Anticholinergic that blocks activation of muscarinic receptors by Ach. Prophylaxis for motion sickness.
ADE scopolamine
sedation, drowsiness, dry mouth
MOA of cyclizine and meclizine
H1 antihistamines that has anticholinergic effects - Piperazine family.
- cyclizine to counter MS
- Meclizine - exerts depressant effect on hyperstimulation of labryinthine release. Used for vesitublar disturbances
MOA of chlorpormazine
block dopamine receptor in CTZ, centrally acting cholinergic as well as antidopamine.
- used for N/V and intractable hiccough
MOA of droperidol
antidoparminergic in CTZ. used for post-op N/V
MOA of metoclopramide
antidopaminergic that blocks chemotherapeutic induced activation of D2 receptors in CTZ. Also stimulates gastric emptying
MOA of granisetron
antiemetic serotonin antagonists
MOA of Dolasetron
antiemetic serotonin antagonists, longer half life than other 5HT3 receptor blockers
MOA of methylprenisolone
anti-emetic effects and reduce side effects when combine w/ other anti-emetics. MOA - prevents production of PGs associated w/ chemo or radiation therapies
MOA of Aprepitant
substance P/neuroknin 1 (NK1) receptor antagnoists used as adjunct drug to prevent emesis induced by cytotoxic chemo drugs.
- crosses BBB and inhibits emesis via central actions
- metabolized by CYP3A4
MOA of lorazepam
benzodiazepine, effect in pts w/ anticipatory vomiting b/c they cause somnolence and amnesia lasting for hours. ususally give 1 day before chemo.
