GI drugs Flashcards
Magnesium Sulfate
increases gastric motility causing DIARRHEA
Aluminum Hydroxide
relaxes small muscle causing CONSTIPATION
Antacids
inorganic base that neutralizes acid and forms salts
HIGH DRUG INTERACTIONS
Food prolongs effects, low systemic absorption
Antacids decrease absorption of
iron, theophylline, isoniazide, quinolones, ketoconazole
Antacids decrease bioavailability of
pheytoin, digitalis, propranolol
Antacids increase elimination of
phenobarbital, salicylates
H2 blockers
-tidine
Decrease NOCTURNAL acid formation, pre-op decrease in stomach acid, prevents stress ulcers
SE of Cimetidine
INHIBITS CYP3A4
LOTS OF DRUG INTERACTIONS
warfarin, phenytoin, benzos, etc
Chronic high doses=anti androgen effects
PPIs
-prazole
irreversibly bind and inhibit H-K-ATPase pump in the parietal cells of stomach
Prevent NSAID ulcers
PRODRUGS, plasma decreases but effect wears on (regardless of when taken)
FEW SE, but may need to supplement Ca2+
Sucralfate
Cytoprotectant
Use: Ulcers
TAKE BEFORE MEAL with NO ANTACIDS
SE: Constipation
Misoprostol
PG analogue cytoprotectant
Ulcer prevetion with NSAID use
CI IN PREGNANCY (used for abortion)
Tritec
bismuth salicylate+metronidazole+tetracycline
Helidac
Ranitidine+bismuch citrate+clarithromycin
Bethanacol
Muscarinic agonist to increase GI tone and motility
POST-OP ILEUS AND INCREASE LES TONE!
SE: Cramping, muscarinic effects
NO CNS EFFECTS
Metoclopramide (Reglan)
DA receptor antagonist to block ACh in GI to increase motility and tone in UGI
ANTIEMETIC
SE: Parkinson-like, EPS, depression, anxiety
METHYLGLOBINEMIA IN NEONATES
DON’T USE IN PGN!
Erythromycin
DOC diabetic gastroparesis
Glycopyrrolate
Dicyclomine
ANTISPASMODICS
Anti-muscarinics used to block vagal input
Decrease intestinal activity and cramping/spasms
SE: ANTICHOLINERGIC TOXIDROME
Alosetron
DO NOT USE! Strictly regulated
Amitriptyline
Anticholinergic effect
Use: IBS to decrease spasticity
SE: MANY!!
-Setron
Ondansetron=Zofran
SELECTIVE 5-HT blocker to the CTZ and GI
ANTIEMETIC
Useful for everything but motion sickness n/v
SE: HA, constipation
Promethazine (Phenergan)
Prochlorperazine (Compazine)
Block DA, muscarinic, and histamine receptors
Use: Post-op nausea, etc INCLUDING MOTION SICKNESS
SE: SEDATION (usually not a terrible thing)
Dronabinol
THC compound
Anti-emetic
Bulk fiber laxatives
increase bulk of feces– DRINK PLENTY OF WATER
SE: Flatulence; impaction and obstruction w/o adequate water
Lactulose
Osmotic laxative
Ion trapping of ammonia (into ammonium in GI) to help decrease NH4 in cirrhosis patients
Polyethylene glycol
GoLytely, Miralax
PREP FOR COLONOSCOPY
NG or oral
Sorbitol
Mannitol
Not used anymore but overuse can cause diarrhea
Senna
Irritant laxative, stimulate peristalsis to enhance secretion and absorption of water
very mild
Biscodyl
Irritant laxative
inhibits absorption of water and stimulates peristalsis
Castor oil
irritant laxative
DON’T USE IN PGN- VERY INTENSE! Requires bile for excretion– don’t use with obstruction
Mineral oil
Docusate sodium
Glycerin
Not very effective as laxatives, act more as stool softeners
Docusate sodium=emulsifying agent
Lubiprostone
PG E1 derivative
increases intestinal secretions to increase motility
Stool softener, does not alter serum electrolytes
DOES NOT PRODUCE TOLERANCE
Sulfasalazine
DOES NOT WORK VIA COX, requires colonic bacterial activation
USED FOR UC
Bulk forming laxatives
First line treatment for diarrhea
Loperamide (imodium)
Opioid analogue to decrease peristalsis
OTC, no CNS effect so low abuse potential
Diphenoxylate + Atropine (Lomotil)
Some CNS effect but decreased with atropine combo
Bismuth subsalicylate (Pepto)
Traveler’s diarrhea
absorbs excess water, may absorb toxins and destroy pathogens– salicylate may inhibit PG synthesis to decrease secretion and inflammation
Produces BLACK STOOL (sometimes)
Contraindications to opioid anti-diarrheal use:
1) due to organisms
2) UC
3) opioid abuse history
