GI Flashcards
PPI’s
o MOA, indications/contraindications, common side effects/adverse effects
decrease acid secretion by acting on proton pump - pariteal cells.
peter pail IS such an azole.
- Block acid secretion by irreversible binding to an inhibiting the hydrogen potassium atpase pump in the parietal cell
- Strong inhibitors of gastric acid secretion through inhibition of proton pump, preventing pumping or release of gastric acid.
o AZOLE. - First line for PUD, - can be used in ger, h pylori, nsaid associated ulcerls, Zollinger Ellison
- Decrease acid secretion. By up to 95%
- 4-8 week treatment.
- Work best if taken before breakfast
- Metabolized y cyp450 system
- Can result in malabsorption – b12, iron, magnesium
- Don’t give as same time at H2RA!!
- Avoid in elderly ( beers) for more than 8 weeks
- Linked to c – diff.
- Increased risk of kidney disease
- Increased rate of pneumonia,
- Fractures
- Dementia and MI – possible risk –
- Inhibits warfarin, diazepam and phenytoin
- Pantoprazole better option – give to patient on clopidogrel
- E careful with antacids and antibiotics – specifically tetracyclines – so separate doses yb at least 4 hours
- Don’t chew or crush – long term users need to taper off.
h2 BLOCKERS
o MOA, indications/contraindications, common side effects/adverse effects
- Bind to histamine 2 receptor on gastric parietal cells to reduce gastric acid secretion
- Ranitidine ( interacts with warfarin)
- Cimetidine ( interacts with more than 100 meds)
- Famotidine
- Nizatidine
- Suppress gastric secretion
- Few SE
- Avoid in patients with delirium 9 beers)
- Clinical response does not preclude the presnse of gastric malignancy!
- Slower onset but better at decreasing severity of symptoms
- Not effective for those with erosive esophagitis
- Preffered as first line in thos with more than occasional symtoms
- Dosed twice dialy
ANTACIDS
o MOA, indications/contraindications, common side effects/adverse effects
- Calcium carbonate – intermediate acting
- Sodium bicarbonate - fast acting
- Aluminum hydroxide
- Aluminum carbonate – slow onset
- Magnesium hydroxide – rapid onset moderate duration
- Combo products
Moa: neutralize gastric hcl – increases PH of the stomach and duodenum
Amount of 1meq hcl brought to ph 3.5 by an atacid solution within 15 minutes
Anc = amount of acid that it can neutralize.
FDA requires a min of 5meq / dose
As the ANC increases the neutralizing capacity of an antacid increases
Suspensions have greater anc than powders or tablets
Sodium and calcium bicarb have the greatest neutralizing capacity
Antacids are best taken after meals 1 hr
Only stays in stomach 20 min if taken before a meal
Liquid or tablet
Side effects:
Calcium carbonate – constipation
Aluminums – constipation
Magnesium hydroxide – diarrhea
Sodium bicar – increase sodium levels – fluid retention
Avoid magnesium antiacids with renal disease due to impaired excretion
MOA: - Increases gastric ph – changes the solubility and disintegration of other drugs - Binds to drugs - Increase urinary ph – which can inhibit excretion, and enhance elimination of weakly acidic drugs Potential interactions - Asa - Benzos - Anticoag - Phenytoion - Digoxin - Nitro - Tertra - Pehnothaizines - Synthryoi - Histamine receptor antagnoists
CYTOPROTECTIVE
o MOA, indications/contraindications, common side effects/adverse effects
- Cover ulcer creating a barrier and promoting healing
- Does not netutralize acid
- Minimal systemic absotpion
- May increase absorption of other drugs
- Don’t take with antacids
- Empty stomach
- 4-8 weeks
- Constipation common side effect
- Caution in renal failure due to aluminum content
- MISOPROSTAL – acts on prostaglandins
o Stimulates gi pathway leading to decrease in gastric acid release
o For treatment of nsaid induced injury
o Side ef. Diareeah, pain, cramps
o Don’t give to womens of child bearing years uness reliable method of birth control
o Can cause birth defects and premature bith abortifacient
Cytoprotective meds - Miso, sulcrafate
LAXATIVES
o MOA, indications/contraindications, common side effects/adverse effects
- 1ST LINE - Bulk laxatives o Psyllium o Methylcellulose o Calcium polycarbophil o Bran o Water o Not systemically absorbed
- 1st line if issue is hard dr stools – Emollients / surfactants o Docusate sodium (Colace) o Docusate calcium o Soften stool o Well tolerated o Not systemically absorbed - Simulants o Bisacodyl ( doclax) o Senna o Castor oil o Act directly on intestinal mucosa to stimulate peristalsis o Useful in constipation due to decreased moblity neurogenic bowel, drugs o Not long term – can lead to dependance o Can cramp o Docolax – works quickly oral 6-12 hours suppority 15 minutes - Saline laxatives o Draw water into intestinal lumen o Magnesium hydroxide o Magnesium sulfate o Mag citrate o Sodium phosphate o Risk of dehydration, renal failure, electrolyte imbalance, hypermagnesemia - Hyperosmolar/ osmotic laxatives o Lactulose o Sorbitol o Glycerol o Polyethylene glycol o Draw water from extravascular pace into intestinal lumen o Do not contain electrolytes like saline laxatives - Enemas o Sodium phosphate o Soap suds o Tap water o Oil retention o Saline o Work by inducing evacuation as a response o Not given prior to disimpaction o Electrolyte imbalances are a risk
Opioid induced constipation
- 1st line is laxative therapy
- If not working trying a peripherally acting mu opioid receptor antagonist pamora or lubiprostone
ANTIDIAREEAHL
o MOA, indications/contraindications, common side effects/adverse effects
o Absorbents
Bismuth subsalicylate
• Stimulates absorption of fluids by the intestine
• Reduces hypermotility of the stomach
• Reduces inflammation
• Binds bacterial toxins
• Weak antacid properties
• Can cause black stools and tongue – tinnitus = signs of toxicity
• Give for diarrhea, nausea, Gerd,
• Caution of also taking aspirin
o Opiates
Agonist at mu opioid receptors
• Decreases fluid secretions
• Increases fluid absorption
• Decreases propulsive contractions
• Increases segmenting contractions
• Delays gastric emptying
• Adverse effects
o Constipation
o Cns effects
o Analgesics that can be used as antidiarrheals
Morphine
Codeine
Loperamide
• Mu opioid agonist
• Very little distribution into CNS so low risk of addiction
• Side effects
o Fatigue, dizzy, nausea, vomit, dry mouth, abdominal cramps, anorexia, paralytic ileus, urinary retention, rash, constipation
o Avoid in patients with fever or bloody stools
Diphenoxylate
• Mu opioid agonist
• High doses can cause euphoria and physical dependance
• Schedule 2 drug alone, schedule v with atropine
• Atropine is an anticholinergic
• Avoid in patients with fever or bloody stool
ANTI EMETICS
o MOA, indications/contraindications, common side effects/adverse effects
- Antihistamine – anticholinergics
o Block the physiological action of histamine ( h1) / acetocholyine at the receptor
o Interrupts visceral afferent pathways that are responsible for stimulating nausea and vomiting reflex
o Most common for motion sickness
o Can be used for vertigo, nausea in pregnancy
o Cheap
o Side effect – sedation, dry mouth, constating urinary retention, blurry vision
o Avoid alcohol
Dimenhydrinate
Hydroxyzine
• Antihistamine effects – also used for severe itching
Meclizine
• 1st line for bppv
• Promethazine
o With codeine as cough syrup
Scopolamine
• Motion sickness, post op
• Also at end of life to dry secretions - Dopamine antagonists
o Centrally acting : inhibiting the dopamine receptors in the medullary chemoreceptor trigger zone
Neuroleptic
Promethazine and prochlorperazine are common as antiemetics as they are the least sedating and require lower dosing for antiemetic effect
Blurred vision, dry mouth, dizzy, restless, seizures, extramyrmidal effects, tardive dyskinesia
Contraindicated in
• Allergy.
• Glaucoma
• Liver disease
• Prostate / bladder probs
Compazine is the most common in this class. But must monitor for extrapy affects.
• Other drugs in this class are used as anti psychotics
o Chlorpromazine
o Fluphenazine
Phenothiazines – potentiates alcohol , cns depressants, bb’s, alpha blockers, Hypotension with thiazide diuretics ,Monitor digoxin, lithium and anticoags
o Peripherally acting: block the vagus nerve in the gastro tract resulting in stim of GI motility
Phenothiazines
• Metoclopramide central and peripheral activity
o Inhibits dopamine and enhances gi motility and gastric emptying
• Common for gastroparesis
• And chemo
• Can have extrapyramidal effects
• S;e – diarrhea, fatigure, qt prolongation
• Avoid in elderly – beeers
o
Pregnancy N/V
First line - Pyridoxine ( vitamin b6) with or without doxylamine
2nd line – ondansetron
Ginger
seretonin antagonists
- inhibit emesis mediated through 5 ht receptors both in eriphery and cns, with primary affects being in the gi tract.
- used for chemo, and prevention post op. - can be used in pregnancy,
- ondansteron - most common. po, sublingual or iv
usually well tolerated, - headache constipation, monitor lfts can prolong qt internval or qrs widening
