viral causes of gastroenteritis
NOROVIRUS, ROTAVIRUS, adenovirus etc
bacterial causes of gastroenteritis
salmonella, campylobacter jejuni, shigella, e. coli
protozoal causes of gastroenteritis
giardia, cryptosporidium
recently on course of abx (clindamycin) and suddenly keeps shitting pants what do you suspect
c.diff
acute diarrhea mainly caused by
infectious source or med side effect
causes of persistent/chronic diarrhea
celiac, hyperthyroidism, microscopic colitis, lactose intolerance, irritable bowel disease, IBD
when are diagnostics for diarrhea needed
sever symptoms : severe dehydration, bloody stool/rectal bleeding, weight loss, severe abd pain, prolonged symptoms (>1 wk), recent hospit/antibiotics, >65yo, comorbidities such as HIV or DM, pregnancy
selectively antagonizes serotonin 5HT3 receptors
zofran (ondansetron)
zofran (ondansetron) administered forms
IV, IM, PO, ODT
zofran (ondansetron) indications
N/V prevention; maybe for chemo or post op, off label use for hyperemesis gravidarum; effective, expensive,
does zofran (ondansetron) or Phenergan(promethazine) or lomotil need dosing adjustment for renal or liver dysfunction
NO
zofran (ondansetron) side effects
few; most common are HA, and constipation; QT prolongation, serotonin syndrome(in combo with other serotonergic agents)
pregnancy category B BUT readily crosses placenta
zofran (ondansetron); possible adverse fetal event associated with zofran (ondansetron) use in pregnancy
caution if administered to nursing women
zofran (ondansetron); not known if it is excreted into breast milk
can cause dose-dependent QT interval prolangation
zofran (ondansetron); avoid with other meds that prolong QT interval (class 1 and 3 antiarrhythmics; 32 mg dose taken off market bc of torsades; NO current recommendation to obtain EKG prior
Phenergan forms
IM, PO, rectal, IV?
Phenergan moa
phenothiazine derivative with antidopaminergic effect; blocker of mesolimbic DA receptors and ALPHA ADRENERGIC Receptors in brainl anithistamine effect H1-receptor blocker
Phenergan indications
symptom tx of allergic conditions, antiemetic, motion sickness, sedative, adjunct to post op analgesic and anesthesia; off label for N/V in pregnancy; relatively inexpensive,
why do you not want to administer Phenergan by IV
severe chemical irritation and damage to tissues; adverse rxns can include burning, pain, thrombophelebitis, tissue necrosis, gangrene, aputation; IM preferred
Phenergan contraindications
children
Phenergan pregnancy category
C
Phenergan side effects
sedation, resp depression; CAUTION with other CNS depressants
Reglan (metocloperamide) forms
IV, IM, PO, ODT
Reglan (metocloperamide) MOA
BLOCKS DA RECEPTORS; blocks serotonin receptors in CNS with high doses; enhances RESPONSE TO ACH in tissue of upper GI tract causes ENHANCE MOTILITY AND ACCELERATED GASTRIC EMPTYING and INCREASES LES tone
Reglan (metocloperamide) indications
antiemetic, promotility agent, GASTROPARESIS (DM) and GERD; inexpensive
Reglan (metocloperamide) side effects
boxed warning TARDIVE DYSKINESIA (mvmt disorder that is often irreversible-increased risk with long duration of tx and total cumulative dose); EPS (generally acute DYSTONIC RXNS), can cause DEPRESSION in pts w and w/o underlying depressive disorders,
AVOID IN GI obstruction
Reglan (metocloperamide)
Compazine (prochlorperazine) forms
IV, IM, PO, rectal
Compazine (prochlorperazine) MOA
piperazine phenothiazine ANTIPSYCHOTIC which BLOCKS POSTSYNAPTIC mesolimbic DA receptors in the brain; exhibits strong ALPHA ADRENERGIC and ANTICHOLINERGIC BLOCKING EFFECT; believed to depress RAS thus effecting basal metabolism body temp wakefulness vasomotor tone and EMESIS
Compazine (prochlorperazine) indications
severe N/V; off label for migraine; historically used for psychotic disorders
Compazine (prochlorperazine) boxed warning side effect
boxed warning-DEMENTIA( elderly with demetia related psychosis tx with antipsychotic drugs at increased risk of death;
Compazine (prochlorperazine) side effects with IV admin
HYPOTENSION
causes akathisia (inner restlessness and a compelling need to be in constant motion)
Compazine (prochlorperazine) side effects; decreased if given with benadryl
many drug interactions
Compazine (prochlorperazine), Phenergan, lomotil
Imodium OTC MOA
Acts DIRECTLYon circular and
longitudinal intestinal muscles, through the OPIOID
receptor
INHIBIT PERISTALSIS and PROLONG TRANSIT TIME
Reduces fecal volume, increases viscosity, and
diminishes fluid/electrolyte loss
Increases tone on the anal sphincter
Imodium OTC INDICATIONS
CONTROL and symptom relief of CHRONIC DIARRHEA ASSOCIATED with IBD and of ACUTE NONSPECIFIC DIARRHEA; OTC and INEXPENSIVE
Imodium OTC DOSING
oral: 4mg followed by 2 mg after each loose stool; up to 16 mg/d
Imodium OTC pregnancy category
C; enters breast milk/not recommended
Imodium OTC side effects
well tolerated but can see dizziness, constipation, abd cramping, nausea
when to d/c Imodium
constipation, abd pain, abd distension, blood in stool; may be dealing with bacterial diarrhea, may precipitate hemolytic uremic syndrome
may precipitate hemolytic uremic syndrome
imodium
when not to used immodium
when peristalsis inhibition should be avoided due to POTENTIAL FOR ILEUS, and/or TOXIC MEGACOLON
Lomotil (diphenoxylate/atropine) MOA
INHIBITS GI PERISTALSIS; sub therapeutic atropine makes OD unlikely
when to d/c Lomotil (diphenoxylate/atropine)
if NO REPSONSE IN 48HRS of continuous therapy bc med is unlikely to be effective (bacterial source)
Lomotil (diphenoxylate/atropine) dosing
oral: 5mg 4 times a day to acheive control max 20 mg/day
Lomotil (diphenoxylate/atropine) pregnancy category
C
lomotil should not be used in
children under 2yo
precautions for lomotil
BLOODY or SUSPECTED BACTERIAL DIARRHEA
CAUTION with lomotil
SEVERE DEHYDRATION OR ELECTROLYTE IMBALANCE
Lomotil side effects
resp depression (seen if with other sedatives), toxic megacolon, ileus, constipation
contain bismuth subsalicyclate
pepto-bismol, kaopectate
pepto-bismol, kaopectate MOA
ABSORBS EXCESS WATER, topical mucosal effects, REDUCES SECRETIONS, binds bacterial toxins, posesses ANTIMICROBIAL EFFECTS
pepto-bismol, kaopectate contraindications
ASA allergy (reyes syndrome), not recommended in pregnancy
pepto-bismol, kaopectate side effects
black stool/tongue
stool softener
colace(docusate sodium) (OTC); inexpensive
colace(docusate sodium) MOA
reduces surface tension of the oil water interface of the stool resulting in ENHANCE INCORPORATION OF WATER AND FAT ALLOWING FOR STOOL SOFTENING
colace(docusate sodium) precautions
acute abdomen, GI obstruction
safe in pregnancy and breastfeeding
colace(docusate sodium)
prolonged, frequent, or excessive, use may result in dependence
colace(docusate sodium)
Lubricant
mineral oil (oral or rectal)
mineral oil mechanism
eases passage of stool by DECREASING WATER ABSORPTION and LUBRICATING THE INTESTINE
if inhaled can cause lipoid pneumonia
mineral oil; caution in elderly, debilitated, infants
Osmotic laxatives
magnesium citrate, polyethylene glycol, lactulose, sodium phosphate
Magnesium citrate MOA
promotes bowel evacuation by causing OSMOTIC RETENTION OF FLUID WHICH DISTENDS THE COLON AND INCREASES PERISTALTIC ACTIVITY; SECRET WEAPON (whatever the fuck that means)
Magnesium citrate precautions
acute abd, bowel obstruction, RENAL IMPAIRMENT (hypermagnesemia),
Magnesium citrate EXTREME CAUTION
patients with myasthenia gravis or other neuromuscular disease
low risk in pregnancy
Magnesium citrate
Magnesium citrate dose
drink 1/2 bottle if no results in 6hrs drink other half
magnesium citrate indication
SECRET WEAPON (whatever the fuck that means)
used in children with severe constipation
miralax
large dose used for colon prep prior to GI surgery
golytely (polyethylene glycol)
lower dose osmotic laxative for acute/chronic constipation
miralax
polyethylene glycol, miralax, golytely MOA
increase WATER RETENTION in the stool INCREASES STOOL FREQUENCY
polyethylene glycol, miralax, golytely precautions
bowel obstructionl electrolyte disturbance may be possible with golytely
Lactulose forms
oral and rectal
lactulose MOA
NONDIGESTABLE SUGAR that causes retention of water causing OSMOTIC EFFECT in the colon with resultant distention promoting peristalsis
traps NH3 in colon and effectively reducing plasma NH3 concentrations and is used for hepatic encephalopathy
lactulose
lactulose pregnancy category
B
Lactulose side effects
well tolerated but diarrhea may be profuse especially in large doses for hepatic encephalopathy
sodium phosphate forms
oral (solution or tablet osmoprep) rectal (fleets enema) and IV (parenteral nutrition and hypophosphatemia)
sodium phosphate MOA
drawing water into the lumen of the gut PRODUCING DISTENTION AND PROMOTING PERISTALSIS and EVACUATION OF THE BOWEL
sodium phosphate indication
BOWEL prep
sodium phosphate black box warning
osmoprep can cause ACUTE PHOSPHATE NEPHROPATHY leading to permanent renal failuer and long term dialysis; caution in elderly, diabetics, renal failure, and CHF
Stimulant laxatives
dulcolax, senna
Stimulant laxatives forms
oral and rectal
Stimulant laxatives MOA
STIMULATES PERISTALSIS by directly irritating the smooth muslce of the intestine; alters water and electrolyte secretion producing NET INTESTINAL FLUID ACCUMULATION and laxation
Stimulant laxatives precautions
acute abdomen, bowel obstruction
Stimulant laxatives side effects
sever rxns are rare; abd cramping, electrolyte disturbance possible, melanosis coli (senna-anthraquinone-containing laxative)
Drug that causes melanosis coli
(senna-anthraquinone-containing laxative)
misc med to tx constipation
amitiza (lubiprostone); relatively expensive
amitiza (lubiprostone) MOA
ACTIVATES CHLORIDE CHANNELS increasing intestinal fluid secretion and motility
amitiza (lubiprostone) indication
IDIOPATHIC chronic constipation, constipation predominant IBS, constipation associated with CHRONIC NARCOTIC HABITUATION
amitiza (lubiprostone) precautions
GI OBSTRUCTION
amitiza (lubiprostone) side effects
NAUSEA, diarrhea, abd pain, HA
indicated for ulcer disease associated with H. pylori infection
abx
mainstays of tx for ulcer healing
anti-secretory drugs (H2 receptor antagonists, and PPIs)
induce ulcer healing but are NOT nearly as effective as H2 blockers and PPIs
antacids and sucralfate
delivers growth factors to injured mucosa and thereby assist in healing
aluminum hydroxide
promote angiogenesis in injured mucosa
antacids
bind bile acids and also inhibit peptic ulcer activity
antacids
suppress but generally DONT eradicate H. pylori
heavy metals
Antacid indication
appropriate for relief of OCCASIONAL
dyspepsia and mild, intermittent GERD
Antacid side effects general info
DEPEND ON THE QUANTITY CONSUMED and the DURATION OF THERAPY;
cause diarrhea and hypermagnesemia
magnesium containing antacids (important in renal insufficiency)
cause constipation
calcium antacids
can cause colume overload in susceptible pts
antacids that may contain considerable sodium
may interfere with absorption or elimination of multiple meds
antacids
antacid drugs
Tums (calcium carbonate) Rolaids (calcium carbonate and magnesium hydroxide) Mylanta (magnesium hydroxide, aluminum hydroxide, simethicone) Maalox (aluminum hydroxide, magnesium hydroxide)
Sulfated polysaccharide, sucrose complexed with
aluminum hydroxide
Sucralfate (Carafate)
Prevents acute chemically-induced mucosal
damage and heals chronic ulcers
Sucralfate (Carafate)
Does not altering gastric acid or pepsin secretion
or significantly buffering acid
Sucralfate (Carafate)
Sucralfate (Carafate) adverse effects
minimal; possible aluminum toxicity; can BIND OTHER DRUGS if taken at the same time
H2 receptor antagonists
cimetidine,
ranitidine, famotidine, and nizatidine; relatively low cost safe in pregnancy, can use PRN
H2 receptor antagonists MOA
Inhibit acid secretion by blocking
histamine H2 receptors on the parietal cell
H2 receptor antagonists indication
TXand MAINTENANCEtherapy of
PUD, treatment of GERD and
management of DYSPEPSIA
Achieve less acid suppression than proton pump
inhibitors
H2 blockers
H2 blocker side effects
SIDE EFFECTS ARE RARE
-Absorption of vitamin B12 depends upon
gastric acid
-not unexpected that LONG TERM H2
blocker (and proton pump inhibitor) use has
been associated with SERUM B12 DEFICIENCY
-renal toxicity, gynecomastia, AMS and dose adjustments should be
made in renal failure
-more common with Cimetidine
PPI drug names
Prilosec (Omeprazole) Rx & OTC
Nexium (Esomerazole) Rx
Prevacid (Lansoprazole) Rx & OTC (PO and IV)
Aciphex (Rabeprazole) Rx
Zegerid (Omeprazole & Bicarb) Rx & OTC
PPI MOA
Block acid secretion by
IRREVERSIBLY binding to and inhibiting the
hydrogen-potassium ATPase pump that resides
on the luminal surface of the PARIETAL CELL(must be active to work cannot be fasting)
membrane
wont work in fasting pts
PPIs
most effective and longest lasting acid inhibitors
PPIs; many are OTC and are relatively affordable
PPI indications
tx of all acid-related disorders including PUD, GERD and ZollingerEllison syndrome -effective in txand preventing NSAID associated gastroduodenal mucosal injury and, -in combo with abx for H. pylori infection
PPI side effects
Hypochlorhydria /hypergastrinemia,
(GASTRIC ATROPHY)
-↓ Magnesium absorption
-↓ Efficacy of Plavix
( inhibit CYP-450s)
-↑ Risk of infection with C. Diff
practical tips for PPIs
Use LOWEST EFFECTIVE DOSE and SHORTEST DURATION
needed
-best given in the MORNING 30-60 min before
eating
for GERD dx hx is sufficient if
tx length
uncomplicated disease (esp
When to do an EGD for GERD
SEVERE DISEASE or associated WORRISOME symptoms (dysphagia, anemie, GI bleeding signs, early satiety, weight loss
EGD will confirm extent of esophageal inflammation which is normal in what % of people
up to 50% is normal
definitve dx for GERD
pH probe with bipsy
tx for mild intermittent symptoms of gerd
antacid and/or H2 blocker; ok to use PRN
tx for moderate GERD symptoms
regular H2 blocker and/or PPI
tx for erosive esophagitis or severe GERD symptoms
definitely PPI, EGD, tx H. pylori if needed
Lifestyle changed for GERD
avoidance of alcohol, tobacco, NSAIDs, decrease stress
