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DERS Pharm > GI Drugs 1 > Flashcards

GI Drugs 1 Flashcards

1
Q

Two major physiological states of gastric acid production:

A
  • Basal

* Meal stimulated

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2
Q

Which drug causes Therapeutic neutralization of low gastric pH protecting esophageal mucosa from reflux corrosion?

A

Antacids

Time of onset: 5 minutes
Duration of action: 30 minutes to 1 hour

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3
Q

Examples of antacids

A

Aluminum hydroxide
Magnesium hydroxide
Calcium carbonate

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4
Q

Antacids shouldn’t be co administered with which drugs ? And why ?

A

tetracyclines, fluoroquinolones, itraconazole and iron

- Increased gastric pH alters dissolution of weakly charged drugs —> decreases the absorption of these drugs

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5
Q

Which antacid causes constipation?

A

Aluminum hydroxide

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6
Q

Which antacid causes osmotic diarrhea ?

A

Magnesium hydroxide

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7
Q

____ and ____ often combine to produce no net change in bowel movements

A

Al and Mg

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8
Q

Which antacid causes Co2 belching and metabolic alkalosis (milk alkali syndrome)?

A

Calcium carbonate

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9
Q

Functions of H2 Receptor antagonists

A
  • Suppress histamine induced gastric acid secretion

* Reduce signal transduction for ACh and Gastrin-induced acid production

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10
Q

Examples of H2 receptor antagonists

A

• Cimetidine: prototype with many adverse effects
• Famotidine, Nizatidine: Second generation with no
anti-adrogenic or CNS adverse effects

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11
Q

_________ strongly suppress basal gastric acid secretion and has a modest effect on meal stimulation secretion

A

H2 Receptor Antagonist

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12
Q

When do you use H2 receptor antagonists

A
  • GERD (Gastro-esophageal reflux disease)
  • PUD (Peptic ulcer disease)
  • Non-ulcer dyspepsia
  • Prophylaxis against stress-related gastritis
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13
Q

Adverse effects of H2 Receptor

A

Increased gastric pH: B12 deficiency and myelosuppression in long-term use

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14
Q

Adverse effects of Cimetidine only

A

• Gynecomastia, galactorrhea, male impotence
- Acts as a nonsteroidal anti-androgen and prolactin stimulant
• Crosses the blood-brain barrier
- Confusion, dizziness and headaches

• Potent inhibition of CYP450 system

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15
Q

Cimetidine increases the serum concentration of which drugs

A
  • Warfarin
  • Diazepam
  • Phenytoin
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16
Q

These drugs Irreversibly bind and inhibit the hydrogen-potassium (H+ - K+) ATPase pump of gastric parietal cells suppressing the final common pathway of gastric acid secretion

A

Proton pump inhibitors

  • Most potent inhibitors of gastric acid secretion
  • Inhibit of 90-98% of 24 hour acid secretion
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17
Q

Effect of PPIs on Gastric Acid Secretion

A

PPIs effectively suppress both basal- and meal- stimulated gastric acid production

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18
Q

Examples of PPI

A 
• Omeprazole
• Esomeprazole
• Rabeprazole 
• Pantoprazole
Lansoprazole
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19
Q

Which type of drugs should be used under these circumstances

• Gastrinoma(ZES)
• Non-ulcer dyspepsia
• Prophylaxis against stress-related gastritis
• Patients who fail twice-daily H2RA therapy
• Severe symptoms of GERD that impair quality of life
• (PUD) Peptic ulcer disease
- NSAID associated ulcers
- Prevention of peptic ulcer bleeding

A

PPI

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20
Q

Adverse effects of PPIs

A
  • Vitamin B12 deficiency due to reduced pepsin function
  • Increased risk of community-acquired pneumonias and C. difficile colitis
  • Hypomagnesemia
  • Osteopenia: possibly via reduced CA2+ absorption or osteoclast inhibition.

• All PPIs carry an FDA-marked mandated warning of a possible increase risk of hip, spine, and wrist fractures

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21
Q

Omeprazole: may inhibit the CYP450 metabolism of:

A
  • Warfarin
  • Diazepam
  • Phenytoin
22
Q

Omeprazole , esomeprazole and lansoprazole reduce the activation of which drug ?

A

Clopidogrel

- because it requires P450 CYP2C19 isoenzyme to be activated and these drugs inhibit CYP2C19

23
Q

How to treat H pylori

A

• Triple therapy: two antibiotics with a PPI
- clarithromycin + amoxicillin + PPI OR
- clarithromycin + metronidazole + PPI
• Quadruple therapy: 2 antibiotics with a PPI and bismuth subsalicylate
- Bisthmus subsalicylate +metronidazole +tetracycline +PPI
• Both regimens: antibiotics given for 10-13 days and the PPI for 1 month

24
Q

This drug is an analog of PGE1; binds the EP3 receptor stimulating the GI pathway to decrease gastric acid secretion; Stimulates mucus and bicarbonate secretion and Enhances mucosal blood flow

A

Mucosal Protective Agents: Misoprostol

25
Q

Properties of misoprostol

A
  • Approved for prevention of NSAID-induced ulcers in high-risk patients
  • Diarrhea, abdominal pain and/or cramps occur in 30% of patients
  • Contraindicated in pregnancy due to abortifacient effects
26
Q

Forms a viscous paste that binds selectively to ulcers

A

Mucosal Protective Agents: Sucralfate

27
Q

Properties of sucralfate

A

Sucralfate: salt of sucrose + sulfated aluminum hydroxide
Forms a viscous paste that binds selectively to ulcers
Negatively charged sucrose sulfate binds positively charged proteins forming a physical barrier
Restricts further caustic damage
Stimulates mucosal prostaglandin and bicarbonate secretion
Limited to the initial management of gastroesophageal reflux disease in pregnancy

28
Q

This drug

  • Suppresses H. pylori
  • Used in quadruple antibiotic therapy of H. pylori-positive ulcers
A

Bismuth subsalicylate

• Pepto-Bismol is widely used for dyspepsia and acute diarrhea

29
Q

Adverse effects of bismuth

A

Harmless blackening of stool
Salicylate toxicity
Contraindicated in patients with renal failure

30
Q

Prokinetic drug groups

A
  • Motilin Agonist

* Serotonin(5HT4) Receptor Agonist

31
Q

Properties of prokinetic agents

A

Should enhance coordinated GI motility
• Act ‘upstream’ of ACh at receptor sites on the enteric neuron, or higher
• Activation of muscarinic (M1) receptors enhance contraction in a relatively uncoordinated fashion
- This produces little or no net propulsive activity
- Thus, the cholinomimetic agent, bethanechol and the Ach-esterase inhibitor neostigmine are not currently preferred for treating GI motility disorders

32
Q

Which prokinetic agent is an

  • Antibiotic
  • Agonist effects at the motilin receptor
  • Rapid down-regulation of motilin receptors leads to early tolerance of this drug. (Use is limited to short courses)
  • Best established indication: diabetic gastroparesis
A

Erythromycin

33
Q

Which prokinetic drug is a

  • 5-HT4 receptor agonist; 5-HT3 antagonist
  • Direct smooth muscle stimulant
  • Was commonly used for gastroesophageal reflux disease, gastroparesis
  • No longer available in the US because of potential to induce serious and occasionally fatal cardiac ventricular arrhythmias
A

Cisapride

34
Q

Which prokinetic drug is a

• 5-HT4 receptor agonist
• Vagal and central 5-HT3 antagonist
• Dopamine (D2) receptor antagonist
• Effects confined to the upper digestive tract
- Increases lower esophageal sphincter tone
- Stimulates antral and small intestinal contractions

A

Metoclopramide

35
Q

When to use metoclopramide

A
  • Gastroparesis
  • Antiemetic
  • GERD for symptomatic relief
36
Q

Adverse effects of metoclopramide

A

Extrapyramidal effects due to Dopamine antagonism

Galactorrhea by blocking the inhibitory effect of dopamine on prolactin release

37
Q

Anti emetic drug list

A
  • Anti-Histamines
  • CholinergicAntagonists
  • D2Antagonists
  • 5-HT3ReceptorAntagonists
  • Corticosteroids
  • Neurokinin-1 receptor Blockers
  • Benzodiazepines
  • Cannabinoids
38
Q

Antimuscarinics- Scopolamine

A
  • Treatment and prevention of motion sickness

* May have some activity in postoperative nausea and vomiting

39
Q

H1 Antagonists examples

A

Diphenhydramine
Meclizine
Cyclizine

40
Q

Function of h1 antagonists

A
  • Histamine H1 antagonists act on vestibular afferents and the brainstem
  • Useful for motion sickness and postoperative emesis
41
Q

This drug is

  • Weak D2 receptor antagonism at the CTZ
  • Sedative Properties are due to antihistaminic and anticholinergic properties effectively treat motion sickness
  • Low to moderately effective in CINV
A

Promethazine

D2 Antagonists- Phenothiazines

42
Q

This drug is a

  • Central Dopaminergic Blockade
  • Potential for adverse extrapyramidal effects
  • Prolongation of QT Interval
A

Droperidol

D2 Antagonists-Butyrophenones

43
Q

Who are the 5HT3 antagonists

A
  • Ondansetron

* Granisetron

44
Q

5HT3 receptors are present in several critical sites involved in emesis including;

A
  • vagal afferents
  • the solitary tract nucleus (STN)
  • chemorecptor trigger zone (CTZ)
  • area postrema (AP)
45
Q

_______________ are the drug of choice for prophylaxis against Acute CINV

A

5HT3 receptor antagonists are the drug of choice for prophylaxis against Acute CINV

46
Q

5-HT3 antagonists are Effective against_________

And Not effective against: ________________

A

Effective against hyperemesis gravidarum

Not effective against: Delayed CINV, motion sickness

47
Q

These drugs work via suppression of peritumoral inflammation and prostaglandin production. They are also highly effective adjuvants in the treatment of nausea in patients with metastatic cancer

A

Dexamethasone

Methylprednisolone

48
Q

These drugs are

Antagonists of the NK1 receptors for substance P
• Indicated for prophylaxis against delayed CINV cause by moderate to highly emetogenic drugs
• Given orally in combination with dexamethasone and 5HT3 receptor antagonist

A
  • Aprepitant

* Parenteral formulation: Fosaprepitant

49
Q

___________ undergoes extensive CYP3A4 metabolism and may affect the metabolism of warfarin and oral contraceptives

A

Aprepitant

50
Q

These drugs

  • Do not have intrinsic antiemetic effects
  • Useful adjuncts due to sedative, amnesic, and anti-anxiety effects which reduce the anticipatory component of nausea and vomiting
  • Facilitate GABAA action in the CNS by increasing the frequency of chloride channel opening
A
  • Lorazepam
  • Alprazolam
  • Diazepam
51
Q

Adverse effects of benzodiazepines

A

CNS depression and dependence

52
Q

Adverse effects of cannabinoids

A
  • Palpitations
  • Hypotension
  • Tachycardia
  • Conjunctival injection (bloodshot eyes)
  • Vasodilation
  • Paranoid reactions and thinking abnormalities
  • Abrupt withdrawal of dronabinol, abstinence syndrome

DERS Pharm (9 decks)

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