(quizlet) Pharm E1: GI

what are the pharmacologic options for GERD?

antacids +/- alginic acid

H2-receptor antagonists

PPI

prokinetics

mucosal protectants

which drugs can cause GERD?

1. anticholinergics

2. narcotics

3. CCB

4. nitrates

5. theophylline

6. quinidine

7. bisphosphonates

8. potassium/iron salts

9. aspirin and NSAIDs

which drugs neutralize acid directly in the stomach?

antacids

sodium bicarb

calcium carbonate (tums)

aluminum hydroxide

magnesium hydroxide

what are the effects of sodium bicarb?

- fluid retention (Na retained→ consider this in Cardio/preg patients)

- produce gas

- increased pH increases gastrin release

which antacids can cause increased kidney pH and kidney stones?

calcium carbonate (tums)

which antacid is contraindicated in appendicitis?

aluminum hydroxide (amphagel)

and milk of magnesia

which antacids are constipating?

calcium carbonate (tums)

aluminum hydroxide (amphagel)

what is the MOA of amphagel?

decreases phosphate absorption

which antacid has drug interactions d/t chelation?

aluminum hydroxide (amphagel)

which antacid causes diarrhea?

magnesium hydroxide (milk of magnesia)

which antacid is contraindicated in renal failure, appendicitis, and intestinal obstruction?

milk of magnesia

why are aluminum hydroxide and magnesium hydroxide commonly used together?

amphagel causes constipation, milk of magnesia causes diarrhea

combo drugs = mylanta and maalox

why should you avoid sodium bicarb in pregnant patients?

edema risk

which drug reacts with Na bicarb and saliva to form a viscous solution?

alginic acid

which drugs reduce gastric acid secretion?

H2 receptor antagonists (-tidine)

why should you not use cimetidine?

strong CYP3A4 inhibition

why may H2RA and PPIs be used IV?

to reduce stress ulcers from overproduction of cortisol

should you adjust dose of H2RA in renal impairment

yes

Can H2RAs be used in pregnancy?

yes, cat B

which drugs irreversibly inhibit the proton pump?

PPIs (-prazole)

what are the adverse effects of PPIs?

- hyperplasia of parietal cells

- elevated stomach pH

- bacterial infections

- hypergastrinemia

- decreases calcium absorption (bc calcium likes to be absorbed in acidic environment)

which drugs are better at healing severe esophagitis and providing sx relief?

PPIs

why should PPIs not be chewed or crushed?

they are not stable in acidic environment → meant to be absorbed in intestine

which drug is a gastrin inhibitor?

Octreotide (Sandostatin) → parenteral only

which drugs are mucosal-protecting agents?

pepto-bismol

sucralfate (carafate)

misoprostol

which drug imparts a black color to oral cavity and feces?

pepto bismol

which drug should you not use in children <16 with fever d/t presence of salicylates?

pepto bismol

What is the MOA of misoprostol?

Prostaglandin E1 analog that increases mucus secretions, reducing acid secretions → used in ulcers caused by nsaids

can misoprostol be used in pregnancy?

NO → used for chemical abortion

what is the MOA of pepto-bismol?

enhances cytoprotective factors, inhibits pepsin activity

what are the causes of PUD?

H. pylori

NSAIDs-induced ulcers

stress-related damage (cortisol)

what are the available treatments for PUD?

PPIs

H2RAs

sucralfate

antacids

drugs to eliminate H. pylori

depends on the cause of the ulcer

what are the non-pharm therapies for PUD?

- eliminate or reduce stress

- avoid trigger foods and eat smaller meals

- avoid NSAIDs, Decrease dose of NSAIDs, switch agent

- EtOH/smoking cessation

what agents are used to tx H. pylori?

- abx → clarithro, amox, flagyl, tetracycline

- BSS (bismuth subsalicylate)

- H2RA

- PPI

which one would be most sufficient to treat a pt with H. pylori-induced ulcer?

*** potential test q

Pt on omeprazole, nizatidine, clarithro/amox, why is this incorrect for tx of H. pylori induced ulcer?

PPI + H2RA

4 drug regimen= want bismuth

what is the MOA of bismuth?

local gastroprotection via stimulation of endogenous PGs also suppress H. pylori

what treatment regimens are preferred for H. pylori ulcers?

4 drug regimen is preferred → bismuth, flagyl, tetra, PPI

could do 3 drug regimen → clarithro, amox, PPI

what regimen is used for failure of H. pylori treatment?

omeprazole

amox

metronidazole (flagyl)

what are the risk factors fo NSAID-induced ulcers?

- age >60

- hx of PUD or GI bleed

- concurrent use of corticosteroids

- high dose and multiple NSAID use

- concurrent use of anticoag

- chronic major organ impairment

what is the pathophys for NSAID-induced ulcers?

direct topical irriration of gastric epithelium

inhibition of COX-1 → prevents synthesis of GI mucosal PG

what are the tx options for NSAID-induced ulcers?

- stop NSAID

- eval for H. pylori

- H2RAs/PPIs/sucralfate (PPI preferred)

what agents are used for prevention of NSAID-induced ulcers?

misoprostol

PPIs

H2RAs

what is the MOA for misoprostol?

synthetic PgE1 analog which provided mucosal PGs

pregnancy category X!

when can misoprostol be used for maintenance of healed ulcers?

if NSAIDs are continued

could also use PPI in this circumstance

which anti-emetic has only antimuscarinic actions?

scopolamine

benefit = not sedating

what are the side effects of scopolamine?

dry mouth

blurred vision

urinary retention

which anti-emetics are anti-muscarinic and anti-histaminic?

- dramamine

- meclizine

- hydroxyzine

- benadryl

- glycopyrrolate

- hyoscyamine

ADR = sedation, anti-muscarinic effects

which anti-emetic would be best for someone going on a cruise?

scopolamine

bc only anti-muscarinic = no sedation

which anti-emetics have anti-serotinergic actions?

- zofran

- dolasetron

- granisetron

- 5-HT3 RA

what are the adverse reactions for anti-serotonergic anti-emetics?

HA

diarrhea

constipation

QT prolongation

which anti-emetic is good for chronic drooling?

glycopyrrolate

which anti-emetic is good for abdominal cramping?

hyoscyamine (levsin)

which anti-emetics are useful in chemotherapy?

anti-serotonergics

which anti-emetics are anti-dopaminergic?

- metoclopramide

- phenothiazines → compazine, haldol, Phenergan

what are the adverse reactions of anti-dopaminergic anti-emetics?

- dizziness, fatigue

- seizures

- sedation

- increased prolactin

- neuroleptic malignant syndrome

which anti-dopaminergic is more likely to cause neuroleptic malignant syndrome?

haldol

which cannabinoids are used for anti-emetic effects?

dronabinol (marinol)

nabilone (Cesamet)

Delta 9 oral formulation

which drugs can be used to treat n/v from chemo when other agents fail?

cannabinoids → central action on vomiting center

also useful for appetite stimulation!

what are the adverse reactions of cannabinoids?

confusion

euphoria

dizziness

incoordination

hallucinations

mood change

orthostatic hypotension

increased appetite

which substance P antagonists may be used for anti-emetic effects?

aprepitant (emend) → used for vomiting d/t cisplatin (chemo) in acute AND delayed phase

which drug helps treat N/V in the delayed phase of emesis d/t cisplatin?

aprepitant

CYP3A4 inhibitor!

which corticosteroids are used in chemo-induced N/V?

dexamethasone

prednisone

which drugs are useful as anxiolytics prior to anticipatory N/V?

benzos → ativan and xanax

which route should you consider for anti-emetics?

sublingual

IV

rectal

prob avoid PO

which drugs are prokinetics?

reglan

erythro

increase gastric emptying

which drugs may induce constipation?

opioids

anticholinergics

antacids

iron

CCBs

what are the indications for laxatives?

1. prepare for bowel surgery

2. hasten bowel excretions of toxins

3. post-operative stimulation

4. minimizing straining in pt with CV dz

5. relief of temporary constipation

in which dx is laxative use contraindicated?

underlying bowel disease

what are the general side effects of laxitives?

acute → N, abd cramp, Diarrhea

chronic → mucosal inflammation, atrophy of outer muscle layers, damage to nerve plexus, malabsorption, dehydration, protein loss, disruption of intestinal flora

what are the 3 categories of laxatives?

1. soften in 1-3 days (bulk-forming agents, emollients, osmotic agents)

2. soft/semi-fluid stools in 6-12 hrs (stimulants)

3. watery evacuation in 1-6 hrs (osmotic laxatives, enemas, bowel clean outs)

which laxatives are bulk-forming?

- psyllium (metamucil)

- methylcellulose (citrucel)

non-digestible fiber→ increase bulk and water content of stool → increase motility

which laxatives are stool softeners?

Docusate sodium (Colace)

mineral oil

glycerin

emulsified with stool → increase water content and lubricate

which laxatives are stimulants/irritants?

- castor oil → increase motility and water/electrolyte secretion

- senna → increase colonic motility

- bisacodyl (dulcolax) → increase colonic motility

what are the side effects of stimulant laxatives?

Abdominal cramps, weakness,

diarrhea

which laxatives are osmotic agents?

- mag sulfate

- mag hydroxide

- lactulose, mannitol

- sodium phosphate (fleet enema)

- polyethylene glycol (miralax)

increase water content and motility

what may be a cause of fatality in pts using osmotic laxatives?

use of electrolytes in young/old patients → fatalities due to hyperphosphatemia

(particularly sodium phosphate enemas)

why should you not rectally administer drugs to neutropenic patients?

risk of microtears → infection

which opioids are used as anti-diarrheals?

diphenoxylate (Lomotil)

loperamide (imodium)

which anti-diarrheal is used for infectious diarrhea?

pepto-bismol

which drugs are aminosalicylates?

sulfasalazine (Azulfidine)

Mesalamine (5-ASA)

what is the MOA for sulfasalazine?

prodrug of sulfapyridine and 5-ASA (mesalamine) → reduced inflam through inhibition of COX and lipoxygenaase

what may be a CI for sulfasalazine?

sulfa drugs

use mesalamine instead!

which form of 5-ASA would be used for proctitis?

canasa

which form of 5-ASA would be best for left-sided disease?

rowasa

what is the MOA of mesalamine?

reduces inflam through inhibition of COX, lipoxygenase and other possible mechanisms

less adverse effects than sulfasalzine

which form of 5-ASA would be best for proximal disease?

oral → pentasa, lialda, asacol

which corticosteroid has the least systemic effects?

budesonide → extensive 1st pass effect

which immunosuppressants can be used for treatment of IBD?

thiopurines

cyclosporine

methotrexate

what are the adverse reactions of corticosteroids?

weight gain

diarrhea

nausea

glucose intolerance

osteoporosis

cushing's disease

which corticosteroids are used for IBD?

oral → budesonide, prednisone, methylprednisone

topical → colocort, anusol-HC, cortifoam

IV → hydrocortisone, prednisolone, methylprednisolone

know risk of anaphylaxis with MAbs

!!!

which monoclonal abs are used for IBD?

infliximab (remicade)

adalimumab (humira)

which immunosuppressant has risk of nephrotoxicity, HTN, infection, and hirsutism?

cyclosporine (Neoral)

which immunosuppressant has risk of myelosuppression, hepatotoxitiy, infectionss, and dermatologic reactions?

methotrexate

which treatments are used for IBS-C?

- bulk-forming laxatives

- osmotic laxative

- lubiprostone

- TCA/SSRI

- 5HT4 partial agonist (tegaserold)

which treatments are used for IBS-U?

probiotics

TCA/SSRI

antispasmodic

which treatments are used for IBS-D?

- bulk-forming laxatives

- loperamide /cholestyramine

- TCA/SSRI

- 5HT3 antagonist (alosetron)

which drug is used to treat SIBO?

rifaximin

what is the MOA of lubiprostone (Amitzia)?

PGE1 derivative that increases intestinal secretion secondary to Cl channel activation