GI Pharm Flashcards
Candida (fungal) esophagitis
MC in Immunocompromised pts: HIV, post-transplant, Chemo
Sxs: dysphagia, odynophagia, chest discomfort, oral thrush
TX: -azole for 14-21 days
Fluconazole or Itraconazole or IV Capsofungin if cannot swallow
Azole MOA: inhibit CYP 450 enzyme Lanosterol-> to convert to ergosterol which is a vital component of cellular mem
AE: Hepatotoxicity- mild or severe Hepatitis -> monitor LFTs
Viral Esophagitis
MC in immunocompromised pts (HIV, post transplant, chemo)
CMV esophagitis:
TX: Gancyclovir -> inhibits viral RNA/DNA synthesis
nonresponders: Foscarnet
Herpetic esophagitis-> look for other sites (lips/genitals)
TX: Acyclovir 5x a day for 14-21 days
Nonresponders: Foscarnet
Gastroesophageal Reflux Disease (GERD)
Presentation: “Heartburn” symp exacerb by meals, bending over, lying supine, frank regurg
Etiology: hydrochloric acid refluxes from stomach into esophagus
Causes:
GE junction dysfxn
hiatal hernia- portion of stomach herniates up
Truncal obesity
Esophageal Motility disorders
delayed gastric emptying-> diabetes
Barrett’s esophagus- severe and unchecked GERD= permanent mucosal damage-> convert squamous to columnar epithelium - METAPLASIA - INCREASED RISK OF DEVELOPING ESOPHAGEAL CANCER
Tx:
1. life style modifications-> avoid acidic foods, lose weight, no alcohol, stop smoking-> avoid laying supine for 3 hours after eating
2. MIld: OTC Antacids and H2-Receptor antagonists ie Pepcid, zantac
3. Moderate to severe: Proton Pump inhibitors- Prilosec, Protonix
OTC antacids
- Magnesium hydroxide/aluminum hydroxide (Maalox, Mylanta)
NEUTS STOMACH ACID AND INHIBITS PEPSIN ACTIVITY-> CAUSES CONSTIPATION THEN MAGNESIUM NEGATES FACT
-Magnesium: osmotic diarrhea
-aluminum salts: constipation
-given together due to SE
NOT FOR RENAL PTS BC HARD TIME GETTING RID OF ALUMINUM/MAGNESIUM - Antacid/Alginic acid (Gaviscon advance or Double action)
-Alginic acid ->the higher the better-> CAUSE MECHANICAL BARRIER-> GEL FORMS A RAFT
-Tums=Calcium salts-> neut gastric acidity and inhibit pepsin-> INCREASE LOWER ESOPHAGEAL SPHINCTER TONE (LES) REDUCING GERD
Bismuth Subsalicylate
manages: general dyspepsia, heartburn, nausea, vomiting, diarrhea+ traveler’s diarrhea prevention (protective barrier)
MOA:
1. reduce inflam- blocks prostaglandins and cox inhibitor
2. stim reabsorption of fluid in intestine with Na and Cl
3. inhibits intestinal secretions
4. Inhibit bacteria from entering the mucosal surface
AE:
1.ASA allergy
2. black tongue - harmless and will resolve
3. Black stools- Melena with bismuth use
4. prolonged high dose- Salicylate poisoning-> metabolic acidosis-> Neurotoxicity and Tinnitus in toxic doses
GI cocktail
for ER pts w/ ACUTE DYSPEPSIA OR REFLUX ESOPHAGITIS SYMPTOMS TO PROVIDE IMMED RELIEF
-SHOULD NOT BE USED TO RULE OUT CARDIAC ETIOLOGIES OF CP-
slurry
Histamine 2 receptor (H2) antagonists
MOA: bind to gastric PARIETAL CELLS and interferes w/ gastric acid production and secretion
Common blockers:
*Famotidine (Pepcid AC)
*Ranitidine (Zantac)
*Cimetidine (Tagamet)- many interactions bc cyp 450
Nizatidine (axid)
For allergies too, hit other receptors
Indications:
GERD
Gastric ulcer prevention in hospitalized pts
Adjunctive therapy for allergic conditions
AE: safe profile
constipation, diarrhea, headache, fatigue
dose adj in renal dz and can interact with drugs
Proton Pump Inhibitor
PPIS MOST POTENT ACID REDUCING MEDICATIONS AVAILABLE
MOA: Prodrugs that require activation in acidic environ> activated form bind with cysteines in NA/K ATPase-> IRREVERSIBLY INACTIVATING IT
MC:
Omeprazole (Prilosec)
Esomeprazole (Nexium)
Lansoprazole (Prevacid)
Pantoprazole (Protonix)-> IV for HOSPITALIZED PTS
Indications: GERD, Peptic ulcer disease, Tx of H. Pylori, Prevention of stress ulcer, Gastrinoma (secretes gastrin leading to ulcers), acute upper GI bleeding
AE: headache, diarrhea, abdominal discomfort, nausea
*POTENTIAL RISK OF AKI/CKD WITH LONG TERM USE
*INCREASED RISK OF VENTILATOR ASSOC PNA - ACID KILLS BACTERIA
*INCREASED RISK OF C DIFF
*B 12 DEFICIENCY
*OSTEOPOROSIS
Bottom Line: these are good medications, but we should avoid keeping patients on them for the long term. Get on, get better, and then get off. Consider A Step-Down approach. PPI-> H2 blocker-> OTC antacids on a PRN basis with lifestyle mods.
H. Pylori
Gram Negative Bacillus-> increase risk of Peptic ulcer disease and increase risk of gastric esophageal cancers
Diag:
*1. GOLD STANDARD= Endoscopy w/ a tissue biopsy
*2. H. Pylori stool antigen = accurate and easy
*3. Urea Breath test = accurate but harder to perform
TX: Quadruple therapy
1. Bismuth
2. Tetracycline
3. Metronidazole
4. Omeprazole
TX: Triple therapy
1. Amoxicillin
2. Clarithromycin
3. Omeprazole
ALL FOR 2 WEEKS
then recheck for irradication
metronidazole substituted for amox if pcn allergy
Peptic ulcer disease
Patho: defect in gastric and duodenum extending through muscularis mucosa into deep layers of wall
-mucosal surface compromised in presence of highly acidic environment
RF: H. Pylori infxn, NSAIDS, Crohns dx, Gastrinoma “Zolinger- Ellison syndrome”, stress
TX:
1. discontinue and AVOID NSAIDS
2. TREAT H. PYLORI TO ERADICATE-> QUAD OR TRIPLE THERAPY
3. Provide GI stress ulcer prophyl in critically ill pts
4. ACID SUPPRESSION-> PPI THERAPY
5. consider adding Sucralfate (Carafate) to aid in mucosal healing-> chalk tab to coat ulcer for healing
Mucosal Protective Agents
*Misoprostol (Cytotec)-> Prostaglandin E1 analog (PGE1)
MOA: stimulates gastric secretion of mucin and bicarb-> weekly suppress acid production and replaces GI prostaglandins
*can be used to prevent ulcers for people who require NSAID use
SE: Diarrhea, abdominal pain, cramping, CAN INDUCE LABOR
BBW: DO NOT GIVE TO WOMEN OF CHILDBEARING YEARS UNLESS RELIABLE DOCUMENTED CHILDBEARING YEARS
TERATOGENIC-> CAUSE ABORTION AND UTERINE RUPTURE
- Sucralfate (Carafate)- Chalk-> forms a physical barrier
SE: CONSTIPATION
ACCEPTABLE IN PREGNANCY
Interactions: Many drug interactions bc it can bind to other medications-> separate administration of other oral meds by atleast 2 hours
Acute Upper GI bleeding
Complaints:
1. Hematemesis “Coffee grounds”
2. Melena “tarry stools)
Sources: BLEEDING PEPTIC ULCER #1
Severe esophagitis, esophageal varices, angiodysplasia, portal HTN gastropathy
TX:
1. PPI- Pantoprazole (Protonix) IV- stabilizes then move to BID dosing
2. Octreotide (Sandostatin) given for variceal bleeding causing splanchnic vasoconstriction
Antiemetic therapy
Causes of Emesis: Gi infxn, vertigo, high intracranial pressure, anesthesia SE, se of meds, chemotherapy se, bowel obstruction, pancreatitis, vagal nerve stimulation, migraine headaches, pregnancy-> Hyperemesis gravidarum
Common antiemetics:
1. * ondansetron (Zofran) *
2. premethazine (phenergan)
3. Metoclopramide (Reglan)
Less common:
Antihistamines- benadryl
Antimuscarinics- Scopolamine (motion sickness tx)
Benzodiazepines- Lorazepam (ativan) or Diazepam (Valium)
Corticosteroids- Dexamethasone (for N/V perioperatively)
Cannaboids- used in cancer pts
Ondansetron (Zofran) (first line)
MOA: 5HT3 receptor antagonist-> 5HT3 on vagal nerve cells and the receptor with serotonin induce vomiting
Setting of use: GI illness, perioperatively/ pre or post-anesthesia
~Zofran is probably one of if not the most used antiemetics on the planet today. It is generally safe but its use in pregnancy is discouraged, especially in the first trimester. ~
AE: QT prolongation and contraind in prego 1st trimester for teratogenic effects
Metoclopramide (Reglan) 2nd line
MOA: works on dopamine and serotonin receptors
Uses: motion sickness and n/v with migraine HAs, postop nausea
AE: *Acute dystonia/ Tardive dyskinesia= motor ticks, invol musc movements, extrapyramidal symptoms
CAN AVOID SE IF GIVEN SLOWLY OR WITH BENADRYL
Promethazine (Phenergan) 3rd line
MOA: *Histamine antagonist-> blocking peripheral and central H1 receptors
Uses: N/V, motion sickness, urticaria
AE:
*Extrapyamidal se, can cause tissue damage w/ IV INJ
drowsiness, confusion, blurred vision
Clostridium Difficile
Clostridioides difficile- causative organism of ANTIBIOTIC ASSOC COLITIS-> DISRUPTS NORMAL FLORA
-*clindamycin is a notorius AB
-can form *pseudomembranous colitis
cytotoxins invade colonic mucosa-> inflamm effects produce pseudomembrane
foul smelling diarrhea, get sepsis from, hard to get rid of bc of spore forming-> soap and water and bleach kill
Tx:
- 1st episode mild to moderate colitis -*Metronidazole and Vancomycin= ORAL BC IN GUT
-1st episode w/ severe colitis= VANCOMYCIN
Recurrent:
1st recurrence= Vancomycin
2 or more= Slow Vanco taper-> 2-3 days then Oral for 2-8 weeks
CONTINUED RECURRENCES OR SEVERE RECURRENT COLITIS CONSIDER COLECTOMY TO REMOVE INFECTED BOWEL OR FECAL TRANSPLANT
