GI Pharmacology 1 and 2 Flashcards

1
Q

Who tends to get gastric vs duodenal ulcers?

A

Gastric - older females

Duodenal - younger males

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2
Q

What are considered the high risk vs low risk NSAIDs for causing ulcers?

A

High risk - indomethacin, ketoroLAC (mainly used as analgesic per sketchy), aspirin, piroxicam (think of the sox cam in sketchy)

Low risk: Ibuprofen, diclofenac, naproxen, meloxicam (more COX-2 per sketchy, thus less side effects), especially celecoxib

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3
Q

What are the risk factors for chronic ulcers?

A

Age > 60 years
Concurrent use of corticosteroids / anticoagulants
Use of several or high dose NSAIDs

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4
Q

What are the adverse drug reactions by all H2 receptor antagonists?

A

Headache, drowsiness, fatigue, can cross BBB and cause confusion and dizziness

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5
Q

What adverse drug effects are more specific to cimetidine?

A

Cimetidine - potent inhibitor of CYP450, so rarely used for this release

Also decreases renal excretion of creatinine - remember from renal

Can cause gynecomastia and hyperprolactinemia - think of boobs in sketchy and milk shooting from nose

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6
Q

When do proton pump inhibitors become active? What does it inhibit?

A

They are absorbed as an inactive prodrug and must be absorbed first and enter parietal cells through basolateral surface -> takes around a day to be come effective, and is dose-dependent

Inhibit only ACTIVE H+/K+ ATPase

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7
Q

What are the two recommended triple therapy regimens for H. pylori? How long should therapy last?

A

MOC: Metronidazole, omeprazole, and clarithromycin

or

COA: Clarithromycin, omeprazole, amoxicillin

Therapy should last 14 days

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8
Q

What is the quadruple therapy and when must it be used?

A

PPI + bismuth + tetracycline + metronidazole

Must be used if patient has a penicillin allergy or there has been past macrolide use

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9
Q

What is the mechanism of action of sucralfate and the adverse effect of concern?

A

Undergoes extensive crosslinking in ulcer base if the environment is acidic

Concern - contains aluminum hydroxide -> special care for patients who may have aluminum overload, i.e. renal failure

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10
Q

What is gastroparesis?

A

Delayed gastric emptying in absence of gastric outlet obstruction or ulceration

-> occurs when vagus nerve is damage or stomach/intestinal muscles are not functioning properly

Causes vomiting and other nonspecific symptoms cause food has nowhere to go

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11
Q

What conditions are especially associated with gastroparesis?

A

Diabetes mellitus

Surgery on stomach or vagus nerve

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12
Q

What two medications are used for gastroparesis and which is used most commonly? What are there mechanisms of action?

A
  1. Metoclopramide - used most commonly - D2 receptor antagonist, and 5HT4 agonist - me tickle guy hanging from the D2 ropes
  2. Domperidone - D2 receptor antagonist

The D2 receptor inhibits Ach release and thus motility if not blocked.

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13
Q

What is one thing that is better about domperidone than metoclopramide but why is it never used?

A

Domperidone doesn’t cross the BBB

It is never used due to QT prolongation -> another side effect of metoclopramide (think of the torsades tapes by the judge’s table)

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14
Q

What are the adverse effects of metoclopramide? What are the contraindications?

A

Increased parkinsonian effects, tardive dyskinesia. (think of the tardive dyskinesia and NMS judge’s table)

Contraindicated in small bowel obstruction (think of the sign in front) or Parkinson’s disease

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15
Q

What is the mechanism of action of erythromycin in the treatment of gastroparesis?

A

Stimulates motilin receptors in smooth muscle cells

-> intestinal peristalsis

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16
Q

What medications lower LES tone?

A

NSAIDs, estrogens, anticholinergics

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17
Q

What is the first-line treatment for GERD if it is intermittent or mild/moderate?

A

Intermittent - antacids, i.e. calcium carbonate

Mild-moderate - OTC H2RA i.e. ranitidine

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18
Q

What is the treatment for severe GERD?

A

max daily dosing of a PPI

Antacids can be used for adjunctive relief as well

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19
Q

What is the acute management of upper GI bleed?

A

Fluid resuscitation with normal saline or lactated ringers

Blood replacement with packed RBCs or fresh frozen plasma, up to 7 mg/dL of Hgb

Endoscopy within first 24 hours to see extent of damage

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20
Q

What is the treatment for esophageal varices vs non-variceal bleeding?

A

Varices - sclerotherapy and variceal ligation

Non-variceal bleeding - electrocautery and epinephrine

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21
Q

What medical therapy must be given following non-variceal upper GI bleed?

A

PPI for at least 72 hours, may be IV drip or taken orally

-> prevents rebleeding

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22
Q

What is the target pH needed for healing of peptic ulcers?

A

Probably around pH 5, must use a PPI to achieve this

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23
Q

What medical therapy must be given for variceal upper GI bleed?

A

PPI infusion, and octreotide

Mechanism - octreotide reduces portal pressures by inhibiting glucagon-mediated splanchnic vasodilation

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24
Q

What are the adverse effects of octreotide?

A

Flushing, edema, abdominal pain, NVD (lack of absorpton due to decreased CCK and digestion)
-> these symptoms may cause further mucosal damage and upper GI bleed, risk

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25
Q

What are the potential adverse effects of PPI’s?

A

Increased risk of C. difficile infection - acid needed to prevent, think of chocolate fountain in sketchy

Increased risk of pneumonia - think of girl with exposed lungs coughing - due to acid needed to clear bacteria

Hypomagnesemia with prolonged use - think of magnets. Can also be associated with hypocalcemia and low iron (H+ needed to absorb these)

26
Q

How is mild vs moderate vs severe ulcerative colitis determined?

A

Mild: <4 stools per day
Moderate: >4 stools per day
Severe: >4 stools per day with evidence of systemic toxicity (fever, leukocytosis, toxic megacolon, etc)

27
Q

What antinflammatory medication class is the first line treatment for ulcerative colitis, especially during acute episodes? What is its mechanism of action?

A

Oral aminosalicylates / 5-ASA preparations, especially mesalamine

Mechanism of action: anti-inflammatory effects via inhibition of prostaglandin and leukotriene synthesis in inflammation

28
Q

What is the major drawbacks of aminosalicylates?

A

Drawback is mostly the high pill burden -> need to ingest 4 grams per day

Many intolerable GI upset effects due to high amount taken (N/V/D)

29
Q

Which aminosalicylate should be avoided in sulfa allergy? Which are considered first line? What guides your choice of a specific one?

A

Sulfasalazine - sulfa allergy

Balsalazide and mesalamine are non-sulfa drugs considered first line

Choice is guided mostly by location of absorption in GI tract -> match it to where you want the drug most, each is different

30
Q

What are the treatment guidelines for acute disease and maintenance therapy in ulcerative proctitis?

A

Acute: 5-ASA enema targeting rectum

Maintenance: same treatment

31
Q

What are the treatment paradigms for acute vs maintenance of ulcerative colitis when it is mostly on the left side vs when it has spread to right?

A

Acute - Oral 5-ASA is preferred in right-sided involvement. Left-sided still 5-ASA enema/suppository

Maintenance: Enema or oral 5-ASA for left-sided. Immunomodulator can be added to oral 5-ASA for right-sided.

32
Q

What is the treatment for severe active ulcerative colitis and then maintenance afterwards?

A

Severe acute - Oral prednisone with 5-ASA + IV steroids if extremely severe

Maintenance - immunomodulator therapy

33
Q

How long may it take to see an improvement in UC symptoms with oral 5-ASA?

A

As long as 4-8 weeks

Can generally be faster with rectal suppository

34
Q

What is the mechanism of action of corticosteroids and how can they cause leukocytosis?

A

Decrease inflammation by upregulating inhibitors of PLA2, inducing apoptosis of lymphocytes, suppress lymphocyte function via inhibiting NF-kB, and inhibiting margination of PMNs

Can cause artificial leukocytosis by causing demargination of PMNs into bloodstream - pg 116

35
Q

What are the side effects of corticosteroids?

A

Cushing syndrome
Adrenal insufficiency - negative feedback causes atrophy
Hyperglycemia / diabetes - insulin resistance and increased gluconeogenesis
Psychosis - insomnia first
Cataracts
Hypokalemia - via mineralocorticoid effects
Osteoporosis with avascular necrosis of femoral head - broken chairleg
Skin thinning / bruising with streaks from capillary atrophy

36
Q

What corticosteroids are typically used in the treatment of ulcerative colitis and when?

A

Typically used in acute episodes only, try to avoid maintenance treatment with it, although about 1/3 of patients are steroid-dependent

Moderate disease -> oral budesonide which is not absorbed, stays in GI tract

Severe disease - IV steroids i.e. methylprednisolone / hydrocortisone

37
Q

What are the non-biologic immunomodulators commonly used in the treatment of both types of IBD? What are the adverse effects of concern?

A

Azathioprine (must be activated by HGPRT) or 6-mercaptopurine

Adverse effects:
Thrombocytopenia
Drug-induced pancreatitis

38
Q

What are two important warnings that need to be shared with those undergoing immunomodulator therapy for inflammatory bowel disease?

A
  1. TNF-alpha inhibitors - can cause reactivation TB, hepatitis B, or predispose to PJP pneumonia
  2. All immunomodulators (including 6-MP) Increased risk for T-cell lymphoma
39
Q

What are the anti-TNF-alpha antibodies which are used as immunomodulators in IBD?

A
  1. Adalimumab
  2. Infliximab
  3. Certolizumab pegol - long-acting
  4. Golimumab

SEE PG 118

40
Q

What other biologic immunomodulator class is being used in IBD? Which is the drug of choice in this and why?

A

Anti-alpha4-integrins - used for WBC adhesion

Vedolizumab - treatment of choice because it doesn’t cross BBB like Natalizumab which is used in the treatment of multiple sclerosis (increased risk of PML)

41
Q

What is the treatment for perianal fistulas in Crohn’s disease?

A

High dose metronidazole, ciprofloxacin, as well as immunomodulators (TNF, integrin, immunosuppressive)

42
Q

Which IBD might nicotine be useful in the treatment of?

A

Ulcerative colitis, since it is associated with non-smokers

43
Q

What is the main underlying difference in the acute treatment of Crohn disease vs ulcerative colitis?

A

Much more heavy reliance on steroids in Crohn disease because the inflammation can be anywhere -> difficult to get immunotherapy to an exact spot

44
Q

What is the overall takehome message of the treatment plan for Crohn’s disease?

A

Oral 5-ASA for acute episodes and maintenance, with steroids if it doesn’t work (prednisone / budesonide)

Oral mesalamine and immunomodulators of all types for maintenance therapy / remission

45
Q

What are the typical dietary triggers of IBS?

A
Large meals
Foods: wheat, rye, barley, chocolate, milk, alcohol
Longterm Abx use
Drinks with caffeine
Stress, conflict, or emotional distress
46
Q

What is the best way to manage IBS?

A

Nonmedical management, i.e.:

  1. Diet modification
  2. Stress management
47
Q

What drugs are the mainstay for antispasmodic treatment for IBS-D? Side effects?

A

Hyoscyamine, dicyclomine

  • > antimuscarinic medications which predominately block Ach release in smooth muscle GI tract
  • > side effects include dry mouth, dry skin, and urinary retention
48
Q

What drug is active on cGMP and is used as a first-line agent for treatment of IBS-C? How does it work?

A

Linaclotide - agonizes cGMP in lumen of intestine resulting in increased bicarbonate and chloride secretion into the GI tract

49
Q

What is Alosetron used for? Mechanism of action?

A

Used for treatment of IBS-D, it is a 5HT3 antagonist (similar to zofran) which is specific to causing constipation in the gut by slowing movement

50
Q

Where is the vomiting center in the brain and what receptors are there?

A

Vomiting center = nucleus tractus solitarius, in the medulla

Receptors: M1, H1, and 5-HT3

51
Q

What are the afferents to the vomiting center?

A

Chemoreceptor trigger zone -
area postrema, at base of fourth ventricular, outside BBB

CN8 - vestibular system

Vagus nerve

Vagal and spinal afferents from GI tract

52
Q

What makes you more likely to vomit during chemotherapy or post-surgery?

A

Chemotherapy - young females who don’t drink alcohol

Surgery - usage of intraoperative and post-operative opioids

53
Q

What is the first-line treatment for nausea in chemotherapy? Mechanism of action and side effects?

A

-setrons i.e. ondansetron dancer

Antagonizes 5-HT-3 receptors in the gut AND the CNS

-side effects: constipation (gut with rope around it), headache (ball hitting head), QTc prolongation (streamer around dancer)

54
Q

What corticosteroid is used in the treatment of nausea / vomiting in chemotherapy? Major adverse effect?

A

high dose dexamethasone
-> causes severe insomnia

Mechanism of action unknown (?prostaglandin inhibition in cortex)

55
Q

What psych drugs are good at stopping nausea and how do they work? Adverse effects

A

Metoclopramide, prochlorperazine

D2 receptor antagonism at area postrema (chemoreceptor trigger zone)

Adverse effects: Drowsiness, akathisia, dystonia, EPS

56
Q

What H1 receptor antagonists are used in the treatment of nausea? What types of nausea are they good at preventing?

A

Diphenhydramine, Meclizine

Good at treating motion sickness and post-operative emesis since they tend to work on inner ear

Cause drowsiness obviously

57
Q

What is the expensive but highly effective drug used as a last line for vomiting during chemotherapy? Adverse effects?

A

Aprepitant - think participant in sketchy

NK1 / Substance P(ee) receptor antagonist in area postrema

Can cause CYP interactions and increase the INR

58
Q

What are the two stimulant laxatives and what is their relative strength?

A

Senna - slow-acting, weak - think of the senna suntan lotion stimulating that man’s belly in sketchy

Bisacodyl - very strong

These both stimulate the enteric nervous system directly and produce strong but brief peristaltic movements

59
Q

What are bulk-forming laxatives and give a few examples?

A

Drugs which increase fecal mass, resulting in stimulation of peristalsis

  • > Psyllium - seaweed
  • > methylcellulose
  • > polyethylene glycol
60
Q

What are two opiate drugs used in the treatment of non-infectious diarrhea?

A
  1. Loperamide - lop-eared bunnies, stimulate GI peristalsis back and forth so there is no net movement
  2. Diphenyoxylate - dolphins, given in combination with atropine to slow bowel movements and also to reduce dependence as diphenoxylate also binds mu and delta receptors in the brain